diff --git a/output/src/out_impls.rs b/output/src/out_impls.rs
index 38a051e..787d752 100644
--- a/output/src/out_impls.rs
+++ b/output/src/out_impls.rs
@@ -49,7 +49,7 @@ impl<N: Coord> WH<N> {
     }
 }
 impl<N: Coord> XYWH<N> {
-    fn zero (&self) -> Self {
+    fn zero () -> Self {
         Self(0.into(), 0.into(), 0.into(), 0.into())
     }
     fn x2 (&self) -> N {
@@ -250,8 +250,13 @@ impl<O: Out> Measure<O> {
     }
 }
 
-impl<O: Out> From<[O::Unit; 2]> for Measure<O> {
-    fn from ([x, y]: [O::Unit; 2]) -> Self { Self::new(x, y) }
+/// FIXME don't convert to u16 specifically
+impl<O: Out> HasWH<O::Unit> for Measure<O> {
+    fn w (&self) -> O::Unit { (self.x.load(Relaxed) as u16).into() }
+    fn h (&self) -> O::Unit { (self.y.load(Relaxed) as u16).into() }
+}
+impl<O: Out> From<WH<O::Unit>> for Measure<O> {
+    fn from (WH(x, y): WH<O::Unit>) -> Self { Self::new(x, y) }
 }
 
 impl<O: Out> Layout<O> for () {
@@ -460,10 +465,10 @@ layout_op_xy!(1 opt: Expand);
 
 impl<O: Out, T: Layout<O>> Layout<O> for Expand<O::Unit, T> {
     fn layout_w (&self, to: XYWH<O::Unit>) -> O::Unit {
-        self.inner().w(to).plus(self.dx().unwrap_or_default())
+        self.inner().layout_w(to).plus(self.dx().unwrap_or_default())
     }
     fn layout_h (&self, to: XYWH<O::Unit>) -> O::Unit {
-        self.inner().w(to).plus(self.dy().unwrap_or_default())
+        self.inner().layout_w(to).plus(self.dy().unwrap_or_default())
     }
 }
 
@@ -703,8 +708,8 @@ impl<'a, O, A, B, I, F, G> Layout<O> for Map<O, A, B, I, F, G> where
     fn layout (&self, area: XYWH<O::Unit>) -> XYWH<O::Unit> {
         let Self { get_iter, get_item, .. } = self;
         let mut index = 0;
-        let [mut min_x, mut min_y] = area.center();
-        let [mut max_x, mut max_y] = area.center();
+        let XY(mut min_x, mut min_y) = area.centered();
+        let XY(mut max_x, mut max_y) = area.center();
         for item in get_iter() {
             let XYWH(x, y, w, h) = get_item(item, index).layout(area);
             min_x = min_x.min(x);
diff --git a/output/src/out_structs.rs b/output/src/out_structs.rs
index b3b14bb..c267a29 100644
--- a/output/src/out_structs.rs
+++ b/output/src/out_structs.rs
@@ -6,7 +6,7 @@ use crate::*;
 /// let xy: XY<u16> = XY(0, 0);
 /// ```
 #[cfg_attr(test, derive(Arbitrary))]
-#[derive(Copy, Clone)] pub struct XY<C: Coord>(pub C, pub C);
+#[derive(Copy, Clone, Default)] pub struct XY<C: Coord>(pub C, pub C);
 
 /// A size (Width, Height).
 ///
@@ -14,7 +14,7 @@ use crate::*;
 /// let wh: WH<u16> = WH(0, 0);
 /// ```
 #[cfg_attr(test, derive(Arbitrary))]
-#[derive(Copy, Clone)] pub struct WH<C: Coord>(pub C, pub C);
+#[derive(Copy, Clone, Default)] pub struct WH<C: Coord>(pub C, pub C);
 
 /// Point with size.
 ///
@@ -25,7 +25,7 @@ use crate::*;
 /// * [ ] TODO: anchor field (determines at which corner/side is X0 Y0)
 ///
 #[cfg_attr(test, derive(Arbitrary))]
-#[derive(Copy, Clone)] pub struct XYWH<C: Coord>(pub C, pub C, pub C, pub C);
+#[derive(Copy, Clone, Default)] pub struct XYWH<C: Coord>(pub C, pub C, pub C, pub C);
 
 /// A cardinal direction.
 ///
@@ -53,7 +53,7 @@ use crate::*;
 /// let measure = Measure::default();
 /// ```
 #[derive(Default)] pub struct Measure<O: Out> {
-    __: PhantomData<O>,
+    pub __: PhantomData<O>,
     pub x: Arc<AtomicUsize>,
     pub y: Arc<AtomicUsize>,
 }
diff --git a/output/src/out_traits.rs b/output/src/out_traits.rs
index 3ce8211..127d1ae 100644
--- a/output/src/out_traits.rs
+++ b/output/src/out_traits.rs
@@ -41,6 +41,32 @@ pub trait Out: Send + Sync + Sized {
     }
 }
 
+/// A numeric type that can be used as coordinate.
+///
+/// FIXME: Replace this ad-hoc trait with `num` crate.
+pub trait Coord: Send + Sync + Copy
+    + Add<Self, Output=Self>
+    + Sub<Self, Output=Self>
+    + Mul<Self, Output=Self>
+    + Div<Self, Output=Self>
+    + Ord + PartialEq + Eq
+    + Debug + Display + Default
+    + From<u16> + Into<u16>
+    + Into<usize>
+    + Into<f64>
+{
+    fn plus (self, other: Self) -> Self;
+    fn minus (self, other: Self) -> Self {
+        if self >= other { self - other } else { 0.into() }
+    }
+    fn atomic (self) -> AtomicUsize {
+        AtomicUsize::new(self.into())
+    }
+    fn zero () -> Self {
+        0.into()
+    }
+}
+
 /// Drawable with dynamic dispatch.
 pub trait Draw<O: Out> {
     fn draw (&self, to: &mut O);
@@ -93,32 +119,6 @@ pub trait HasContent<O: Out> {
 // TODO DOCUMENTME
 pub trait Content<O: Out>: Draw<O> + Layout<O> {}
 
-/// A numeric type that can be used as coordinate.
-///
-/// FIXME: Replace this ad-hoc trait with `num` crate.
-pub trait Coord: Send + Sync + Copy
-    + Add<Self, Output=Self>
-    + Sub<Self, Output=Self>
-    + Mul<Self, Output=Self>
-    + Div<Self, Output=Self>
-    + Ord + PartialEq + Eq
-    + Debug + Display + Default
-    + From<u16> + Into<u16>
-    + Into<usize>
-    + Into<f64>
-{
-    fn plus (self, other: Self) -> Self;
-    fn minus (self, other: Self) -> Self {
-        if self >= other { self - other } else { 0.into() }
-    }
-    fn atomic (self) -> AtomicUsize {
-        AtomicUsize::new(self.into())
-    }
-    fn zero () -> Self {
-        0.into()
-    }
-}
-
 // Something that has an origin point (X, Y).
 pub trait HasXY<N: Coord> {
     fn x  (&self) -> N;
diff --git a/tui/src/tui_content/_tui_focus.rs b/tui/src/.scratch.rs
similarity index 68%
rename from tui/src/tui_content/_tui_focus.rs
rename to tui/src/.scratch.rs
index 41b0f33..a6ee28e 100644
--- a/tui/src/tui_content/_tui_focus.rs
+++ b/tui/src/.scratch.rs
@@ -304,3 +304,131 @@ pub fn to_focus_command <T: Send + Sync> (input: &TuiIn) -> Option<FocusCommand<
         }
     }
 }
+use crate::*;
+pub struct MenuBar<E: Engine, S, C: Command<S>> {
+    pub menus: Vec<Menu<E, S, C>>,
+    pub index: usize,
+}
+impl<E: Engine, S, C: Command<S>> MenuBar<E, S, C> {
+    pub fn new () -> Self { Self { menus: vec![], index: 0 } }
+    pub fn add (mut self, menu: Menu<E, S, C>) -> Self {
+        self.menus.push(menu);
+        self
+    }
+}
+pub struct Menu<E: Engine, S, C: Command<S>> {
+    pub title: Arc<str>,
+    pub items: Vec<MenuItem<E, S, C>>,
+    pub index: Option<usize>,
+}
+impl<E: Engine, S, C: Command<S>> Menu<E, S, C> {
+    pub fn new (title: impl AsRef<str>) -> Self {
+        Self {
+            title: title.as_ref().to_string(),
+            items: vec![],
+            index: None,
+        }
+    }
+    pub fn add (mut self, item: MenuItem<E, S, C>) -> Self {
+        self.items.push(item);
+        self
+    }
+    pub fn sep (mut self) -> Self {
+        self.items.push(MenuItem::sep());
+        self
+    }
+    pub fn cmd (mut self, hotkey: &'static str, text: &'static str, command: C) -> Self {
+     self.items.push(MenuItem::cmd(hotkey, text, command));
+        self
+    }
+    pub fn off (mut self, hotkey: &'static str, text: &'static str) -> Self {
+        self.items.push(MenuItem::off(hotkey, text));
+        self
+    }
+}
+pub enum MenuItem<E: Engine, S, C: Command<S>> {
+    /// Unused.
+    __(PhantomData<E>, PhantomData<S>),
+    /// A separator. Skip it.
+    Separator,
+    /// A menu item with command, description and hotkey.
+    Command(&'static str, &'static str, C),
+    /// A menu item that can't be activated but has description and hotkey
+    Disabled(&'static str, &'static str)
+}
+impl<E: Engine, S, C: Command<S>> MenuItem<E, S, C> {
+    pub fn sep () -> Self {
+        Self::Separator
+    }
+    pub fn cmd (hotkey: &'static str, text: &'static str, command: C) -> Self {
+        Self::Command(hotkey, text, command)
+    }
+    pub fn off (hotkey: &'static str, text: &'static str) -> Self {
+        Self::Disabled(hotkey, text)
+    }
+}
+
+//impl<T: Draw<TuiOut>> Content<TuiOut> for Result<T, Box<dyn std::error::Error>> {
+    //fn content (&self) -> impl Draw<TuiOut> + '_ {
+        //Bsp::a(self.as_ref().ok(), self.as_ref().err().map(
+            //|e|Tui::fg_bg(Color::Rgb(255,255,255), Color::Rgb(32,32,32), e.to_string())
+        //))
+    //}
+//}
+
+//impl<T: Draw<TuiOut>> Draw<TuiOut> for Result<T, Box<dyn std::error::Error>> {
+    //fn layout (&self, to: [u16;4]) -> [u16;4] {
+        //match self {
+            //Ok(content) => content.layout(to),
+            //Err(e) => [0, 0, to.w(), to.h()]
+        //}
+    //}
+    //fn draw (&self, to: &mut TuiOut) {
+        //match self {
+            //Ok(content) => content.draw(to),
+            //Err(e) => to.blit(&e.to_string(), 0, 0, Some(Style::default()
+                //.bg(Color::Rgb(32,32,32))
+                //.fg(Color::Rgb(255,255,255))))
+        //}
+    //}
+//}
+
+        //let token = token.as_ref();
+        //if token.len() < 2 {
+            //Self { valid: false, key: None, mods: KeyModifiers::NONE }
+        //} else if token.chars().next() != Some('@') {
+            //Self { valid: false, key: None, mods: KeyModifiers::NONE }
+        //} else {
+            //Self { valid: true, key: None, mods: KeyModifiers::NONE }.next(&token[1..])
+        //}
+    //}
+    //pub fn build (self) -> Option<Event> {
+        //if self.valid && self.key.is_some() {
+            //Some(Event::Key(KeyEvent::new(self.key.unwrap(), self.mods)))
+        //} else {
+            //None
+        //}
+    //}
+    //fn next (mut self, token: &str) -> Self {
+        //let mut tokens = token.split('-').peekable();
+        //while let Some(token) = tokens.next() {
+            //if tokens.peek().is_some() {
+                //match token {
+                    //"ctrl"  | "Ctrl"  | "c" | "C" => self.mods |= KeyModifiers::CONTROL,
+                    //"alt"   | "Alt"   | "m" | "M" => self.mods |= KeyModifiers::ALT,
+                    //"shift" | "Shift" | "s" | "S" => {
+                        //self.mods |= KeyModifiers::SHIFT;
+                        //// + TODO normalize character case, BackTab, etc.
+                    //},
+                    //_ => panic!("unknown modifier {token}"),
+                //}
+            //} else {
+                //self.key = if token.len() == 1 {
+                    //Some(KeyCode::Char(token.chars().next().unwrap()))
+                //} else {
+                    //Some(Self::named_key(token).unwrap_or_else(||panic!("unknown character {token}")))
+                //}
+            //}
+        //}
+        //self
+    //}
diff --git a/tui/src/lib.rs b/tui/src/lib.rs
index d9e16c6..976d230 100644
--- a/tui/src/lib.rs
+++ b/tui/src/lib.rs
@@ -1,4 +1,9 @@
 #![feature(type_changing_struct_update, trait_alias)]
+
+use std::{time::Duration, thread::{spawn, JoinHandle}};
+
+use unicode_width::*;
+
 pub use ::{
     dizzle,
     tengri_input,
@@ -8,6 +13,7 @@ pub use ::{
     palette,
     better_panic,
 };
+
 pub(crate) use ::{
     dizzle::*,
     tengri_input::*,
@@ -26,11 +32,10 @@ pub(crate) use ::{
     crossterm::{
         ExecutableCommand,
         terminal::{EnterAlternateScreen, LeaveAlternateScreen, enable_raw_mode, disable_raw_mode},
-        event::{Event, KeyEvent, KeyCode, KeyModifiers, KeyEventKind, KeyEventState},
+        event::{poll, read, Event, KeyEvent, KeyCode, KeyModifiers, KeyEventKind, KeyEventState},
     }
 };
-mod tui_engine;  pub use self::tui_engine::*;
-mod tui_content; pub use self::tui_content::*;
+
 #[macro_export] macro_rules! tui_main {
     ($expr:expr) => {
         fn main () -> Usually<()> {
@@ -41,6 +46,256 @@ mod tui_content; pub use self::tui_content::*;
     };
 }
 
+#[macro_export] macro_rules! has_color {
+    (|$self:ident:$Struct:ident$(<$($L:lifetime),*$($T:ident$(:$U:path)?),*>)?|$cb:expr) => {
+        impl $(<$($L),*$($T $(: $U)?),*>)? HasColor for $Struct $(<$($L),*$($T),*>)? {
+            fn color (&$self) -> ItemColor { $cb }
+        }
+    }
+}
+
+macro_rules! border {
+    ($($T:ident {
+        $nw:literal $n:literal $ne:literal $w:literal $e:literal $sw:literal $s:literal $se:literal
+        $($x:tt)*
+    }),+) => {$(
+        impl BorderStyle for $T {
+            const NW: &'static str = $nw;
+            const N:  &'static str = $n;
+            const NE: &'static str = $ne;
+            const W:  &'static str = $w;
+            const E:  &'static str = $e;
+            const SW: &'static str = $sw;
+            const S:  &'static str = $s;
+            const SE: &'static str = $se;
+            $($x)*
+            fn enabled (&self) -> bool { self.0 }
+        }
+        #[derive(Copy, Clone)] pub struct $T(pub bool, pub Style);
+        impl Layout<TuiOut> for $T {}
+        impl Draw<TuiOut> for $T {
+            fn draw (&self, to: &mut TuiOut) {
+                if self.enabled() { let _ = BorderStyle::draw(self, to); }
+            }
+        }
+    )+}
+}
+
+mod tui_structs;  pub use self::tui_structs::*;
+mod tui_traits;   pub use self::tui_traits::*;
+mod tui_impls;    pub use self::tui_impls::*;
+
+#[cfg(feature = "dsl")] 
+pub fn evaluate_output_expression_tui <'a, S> (
+    state: &S, output: &mut TuiOut, expr: impl Expression + 'a
+) -> Usually<bool> where
+    S: View<TuiOut, ()>
+        + for<'b>Namespace<'b, bool>
+        + for<'b>Namespace<'b, u16>
+        + for<'b>Namespace<'b, Color>
+{
+    // See `tengri_output::evaluate_output_expression`
+    let head = expr.head()?;
+    let mut frags = head.src()?.unwrap_or_default().split("/");
+    let args  = expr.tail();
+    let arg0  = args.head();
+    let tail0 = args.tail();
+    let arg1  = tail0.head();
+    let tail1 = tail0.tail();
+    let _arg2 = tail1.head();
+    match frags.next() {
+
+        Some("text") => if let Some(src) = args?.src()? { output.place(&src) },
+
+        Some("fg") => {
+            let arg0 = arg0?.expect("fg: expected arg 0 (color)");
+            output.place(&Tui::fg(
+                Namespace::<Color>::resolve(state, arg0)?.unwrap_or_else(||panic!("fg: {arg0:?}: not a color")),
+                Thunk::new(move|output: &mut TuiOut|state.view(output, &arg1).unwrap()),
+            ))
+        },
+
+        Some("bg") => {
+            let arg0 = arg0?.expect("bg: expected arg 0 (color)");
+            output.place(&Tui::bg(
+                Namespace::<Color>::resolve(state, arg0)?.unwrap_or_else(||panic!("bg: {arg0:?}: not a color")),
+                Thunk::new(move|output: &mut TuiOut|state.view(output, &arg1).unwrap()),
+            ))
+        },
+
+        _ => return Ok(false)
+
+    };
+    Ok(true)
+}
+
+pub fn named_key (token: &str) -> Option<KeyCode> {
+    use KeyCode::*;
+    Some(match token {
+        "up"                => Up,
+        "down"              => Down,
+        "left"              => Left,
+        "right"             => Right,
+        "esc"    | "escape" => Esc,
+        "enter"  | "return" => Enter,
+        "delete" | "del"    => Delete,
+        "backspace"         => Backspace,
+        "tab"               => Tab,
+        "space"             => Char(' '),
+        "comma"             => Char(','),
+        "period"            => Char('.'),
+        "plus"              => Char('+'),
+        "minus" | "dash"    => Char('-'),
+        "equal" | "equals"  => Char('='),
+        "underscore"        => Char('_'),
+        "backtick"          => Char('`'),
+        "lt"                => Char('<'),
+        "gt"                => Char('>'),
+        "cbopen"  | "openbrace"  => Char('{'),
+        "cbclose" | "closebrace" => Char('}'),
+        "bropen"  | "openbracket"  => Char('['),
+        "brclose" | "closebracket" => Char(']'),
+        "pgup" | "pageup"   => PageUp,
+        "pgdn" | "pagedown" => PageDown, 
+        "f1"                => F(1),
+        "f2"                => F(2),
+        "f3"                => F(3),
+        "f4"                => F(4),
+        "f5"                => F(5),
+        "f6"                => F(6),
+        "f7"                => F(7),
+        "f8"                => F(8),
+        "f9"                => F(9),
+        "f10"               => F(10),
+        "f11"               => F(11),
+        "f12"               => F(12),
+        _ => return None,
+    })
+}
+
+pub fn button_2 <'a> (key: impl Content<TuiOut>, label: impl Content<TuiOut>, editing: bool) -> impl Content<TuiOut> {
+    Tui::bold(true, Bsp::e(
+        Tui::fg_bg(Tui::orange(), Tui::g(0), Bsp::e(Tui::fg(Tui::g(0), &"▐"), Bsp::e(key, Tui::fg(Tui::g(96), &"▐")))),
+        When::new(!editing, Tui::fg_bg(Tui::g(255), Tui::g(96), label))))
+}
+
+pub fn button_3 <'a> (
+    key: impl Content<TuiOut>, label: impl Content<TuiOut>, value: impl Content<TuiOut>, editing: bool,
+) -> impl Content<TuiOut> {
+    Tui::bold(true, Bsp::e(
+        Tui::fg_bg(Tui::orange(), Tui::g(0),
+            Bsp::e(Tui::fg(Tui::g(0), &"▐"), Bsp::e(key, Tui::fg(if editing { Tui::g(128) } else { Tui::g(96) }, "▐")))),
+        Bsp::e(
+            When::new(!editing, Bsp::e(Tui::fg_bg(Tui::g(255), Tui::g(96), label), Tui::fg_bg(Tui::g(128), Tui::g(96), &"▐"),)),
+            Bsp::e(Tui::fg_bg(Tui::g(224), Tui::g(128), value), Tui::fg_bg(Tui::g(128), Reset, &"▌"), ))))
+}
+
+border! {
+    Square {
+        "┌" "─" "┐"
+        "│"     "│"
+        "└" "─" "┘" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    SquareBold {
+        "┏" "━" "┓"
+        "┃"     "┃"
+        "┗" "━" "┛" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    TabLike {
+        "╭" "─" "╮"
+        "│"     "│"
+        "│" " " "│" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Lozenge {
+        "╭" "─" "╮"
+        "│"     "│"
+        "╰" "─" "╯" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Brace {
+        "╭" "" "╮"
+        "│"    "│"
+        "╰" "" "╯" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    LozengeDotted {
+        "╭" "┅" "╮"
+        "┇"     "┇"
+        "╰" "┅" "╯" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Quarter {
+        "▎" "▔" "🮇"
+        "▎"     "🮇"
+        "▎" "▁" "🮇" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    QuarterV {
+        "▎" "" "🮇"
+        "▎"    "🮇"
+        "▎" "" "🮇" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Chamfer {
+        "🭂" "▔" "🭍"
+        "▎"     "🮇"
+        "🭓" "▁" "🭞" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Corners {
+        "🬆" "" "🬊" // 🬴 🬸
+        ""     ""
+        "🬱" "" "🬵" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    CornersTall {
+        "🭽" "" "🭾"
+        ""     ""
+        "🭼" "" "🭿" fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Outer {
+        "🭽" "▔" "🭾"
+        "▏"     "▕"
+        "🭼" "▁" "🭿"
+        const W0: &'static str = "[";
+        const E0: &'static str = "]";
+        const N0: &'static str = "⎴";
+        const S0: &'static str = "⎵";
+        fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Thick {
+        "▄" "▄" "▄"
+        "█"     "█"
+        "▀" "▀" "▀"
+        fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Rugged {
+        "▄" "▂" "▄"
+        "▐"     "▌"
+        "▀" "🮂" "▀"
+        fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Skinny {
+        "▗" "▄" "▖"
+        "▐"     "▌"
+        "▝" "▀" "▘"
+        fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Brackets {
+        "⎡" "" "⎤"
+        ""     ""
+        "⎣" "" "⎦"
+        const W0: &'static str = "[";
+        const E0: &'static str = "]";
+        const N0: &'static str = "⎴";
+        const S0: &'static str = "⎵";
+        fn style (&self) -> Option<Style> { Some(self.1) }
+    },
+    Reticle {
+        "⎡" "" "⎤"
+        ""     ""
+        "⎣" "" "⎦"
+        const W0: &'static str = "╟";
+        const E0: &'static str = "╢";
+        const N0: &'static str = "┯";
+        const S0: &'static str = "┷";
+        fn style (&self) -> Option<Style> { Some(self.1) }
+    }
+}
+
 #[cfg(test)] mod tui_test {
     use crate::*;
     #[test] fn test_tui_engine () -> Usually<()> {
diff --git a/tui/src/tui_content.rs b/tui/src/tui_content.rs
index f1c812b..6a3e003 100644
--- a/tui/src/tui_content.rs
+++ b/tui/src/tui_content.rs
@@ -1,12 +1,5 @@
 #[allow(unused)] use crate::*;
-impl Tui {
-    pub const fn fg     <T>    (color: Color, w: T) -> Foreground<Color, T> { Foreground(color, w) }
-    pub const fn bg     <T>    (color: Color, w: T) -> Background<Color, T> { Background(color, w) }
-    pub const fn fg_bg  <T>    (fg: Color, bg: Color, w: T) -> Background<Color, Foreground<Color, T>> { Background(bg, Foreground(fg, w)) }
-    pub const fn modify <T>    (enable: bool, modifier: Modifier, w: T) -> Modify<T> { Modify(enable, modifier, w) }
-    pub const fn bold   <T>    (enable: bool, w: T) -> Modify<T> { Self::modify(enable, Modifier::BOLD, w) }
-    pub const fn border <S, T> (enable: bool, style: S, w: T) -> Bordered<S, T> { Bordered(enable, style, w) }
-}
+
 mod tui_border; pub use self::tui_border::*;
 mod tui_button; pub use self::tui_button::*;
 mod tui_color;  pub use self::tui_color::*;
@@ -17,58 +10,3 @@ mod tui_scroll; pub use self::tui_scroll::*;
 mod tui_string; pub use self::tui_string::*;
 mod tui_number;   //pub use self::tui_number::*;
 mod tui_tryptich; //pub use self::tui_tryptich::*;
-impl<T: Content<TuiOut>> Draw<TuiOut> for Foreground<Color, T> {
-    fn draw (&self, to: &mut TuiOut) {
-        let area = self.layout(to.area());
-        to.fill_fg(area, self.0);
-        to.place_at(area, &self.1);
-    }
-}
-impl<T: Content<TuiOut>> Draw<TuiOut> for Background<Color, T> {
-    fn draw (&self, to: &mut TuiOut) {
-        let area = self.layout(to.area());
-        to.fill_bg(area, self.0);
-        to.place_at(area, &self.1);
-    }
-}
-pub struct Modify<T>(pub bool, pub Modifier, pub T);
-impl<T: Content<TuiOut>> Layout<TuiOut> for Modify<T> {}
-impl<T: Content<TuiOut>> Draw<TuiOut> for Modify<T> {
-    fn draw (&self, to: &mut TuiOut) {
-        to.fill_mod(to.area(), self.0, self.1);
-        self.2.draw(to)
-    }
-}
-pub struct Styled<T>(pub Option<Style>, pub T);
-impl<T: Content<TuiOut>> Layout<TuiOut> for Styled<T> {}
-impl<T: Content<TuiOut>> Draw<TuiOut> for Styled<T> {
-    fn draw (&self, to: &mut TuiOut) {
-        to.place(&self.1);
-        // TODO write style over area
-    }
-}
-
-//impl<T: Draw<TuiOut>> Content<TuiOut> for Result<T, Box<dyn std::error::Error>> {
-    //fn content (&self) -> impl Draw<TuiOut> + '_ {
-        //Bsp::a(self.as_ref().ok(), self.as_ref().err().map(
-            //|e|Tui::fg_bg(Color::Rgb(255,255,255), Color::Rgb(32,32,32), e.to_string())
-        //))
-    //}
-//}
-
-//impl<T: Draw<TuiOut>> Draw<TuiOut> for Result<T, Box<dyn std::error::Error>> {
-    //fn layout (&self, to: [u16;4]) -> [u16;4] {
-        //match self {
-            //Ok(content) => content.layout(to),
-            //Err(e) => [0, 0, to.w(), to.h()]
-        //}
-    //}
-    //fn draw (&self, to: &mut TuiOut) {
-        //match self {
-            //Ok(content) => content.draw(to),
-            //Err(e) => to.blit(&e.to_string(), 0, 0, Some(Style::default()
-                //.bg(Color::Rgb(32,32,32))
-                //.fg(Color::Rgb(255,255,255))))
-        //}
-    //}
-//}
diff --git a/tui/src/tui_content/_tui_menu.rs b/tui/src/tui_content/_tui_menu.rs
deleted file mode 100644
index 3f5ee25..0000000
--- a/tui/src/tui_content/_tui_menu.rs
+++ /dev/null
@@ -1,63 +0,0 @@
-use crate::*;
-pub struct MenuBar<E: Engine, S, C: Command<S>> {
-    pub menus: Vec<Menu<E, S, C>>,
-    pub index: usize,
-}
-impl<E: Engine, S, C: Command<S>> MenuBar<E, S, C> {
-    pub fn new () -> Self { Self { menus: vec![], index: 0 } }
-    pub fn add (mut self, menu: Menu<E, S, C>) -> Self {
-        self.menus.push(menu);
-        self
-    }
-}
-pub struct Menu<E: Engine, S, C: Command<S>> {
-    pub title: Arc<str>,
-    pub items: Vec<MenuItem<E, S, C>>,
-    pub index: Option<usize>,
-}
-impl<E: Engine, S, C: Command<S>> Menu<E, S, C> {
-    pub fn new (title: impl AsRef<str>) -> Self {
-        Self {
-            title: title.as_ref().to_string(),
-            items: vec![],
-            index: None,
-        }
-    }
-    pub fn add (mut self, item: MenuItem<E, S, C>) -> Self {
-        self.items.push(item);
-        self
-    }
-    pub fn sep (mut self) -> Self {
-        self.items.push(MenuItem::sep());
-        self
-    }
-    pub fn cmd (mut self, hotkey: &'static str, text: &'static str, command: C) -> Self {
-     self.items.push(MenuItem::cmd(hotkey, text, command));
-        self
-    }
-    pub fn off (mut self, hotkey: &'static str, text: &'static str) -> Self {
-        self.items.push(MenuItem::off(hotkey, text));
-        self
-    }
-}
-pub enum MenuItem<E: Engine, S, C: Command<S>> {
-    /// Unused.
-    __(PhantomData<E>, PhantomData<S>),
-    /// A separator. Skip it.
-    Separator,
-    /// A menu item with command, description and hotkey.
-    Command(&'static str, &'static str, C),
-    /// A menu item that can't be activated but has description and hotkey
-    Disabled(&'static str, &'static str)
-}
-impl<E: Engine, S, C: Command<S>> MenuItem<E, S, C> {
-    pub fn sep () -> Self {
-        Self::Separator
-    }
-    pub fn cmd (hotkey: &'static str, text: &'static str, command: C) -> Self {
-        Self::Command(hotkey, text, command)
-    }
-    pub fn off (hotkey: &'static str, text: &'static str) -> Self {
-        Self::Disabled(hotkey, text)
-    }
-}
diff --git a/tui/src/tui_content/tui_border.rs b/tui/src/tui_content/tui_border.rs
deleted file mode 100644
index 8f8d11b..0000000
--- a/tui/src/tui_content/tui_border.rs
+++ /dev/null
@@ -1,257 +0,0 @@
-use crate::*;
-
-impl<S: BorderStyle, W: Content<TuiOut>> HasContent<TuiOut> for Bordered<S, W> {
-    fn content (&self) -> impl Content<TuiOut> {
-        Fill::XY(lay!( When::new(self.0, Border(self.0, self.1)), Pad::XY(1, 1, &self.2) ))
-    }
-}
-
-impl<S: BorderStyle> Draw<TuiOut> for Border<S> {
-    fn draw (&self, to: &mut TuiOut) {
-        let Border(enabled, style) = self;
-        if *enabled {
-            let area = to.area();
-            if area.w() > 0 && area.y() > 0 {
-                to.blit(&style.border_nw(), area.x(), area.y(), style.style());
-                to.blit(&style.border_ne(), area.x() + area.w() - 1, area.y(), style.style());
-                to.blit(&style.border_sw(), area.x(), area.y() + area.h() - 1, style.style());
-                to.blit(&style.border_se(), area.x() + area.w() - 1, area.y() + area.h() - 1, style.style());
-                for x in area.x()+1..area.x()+area.w()-1 {
-                    to.blit(&style.border_n(), x, area.y(), style.style());
-                    to.blit(&style.border_s(), x, area.y() + area.h() - 1, style.style());
-                }
-                for y in area.y()+1..area.y()+area.h()-1 {
-                    to.blit(&style.border_w(), area.x(), y, style.style());
-                    to.blit(&style.border_e(), area.x() + area.w() - 1, y, style.style());
-                }
-            }
-        }
-    }
-}
-
-pub trait BorderStyle: Content<TuiOut> + Copy {
-    fn enabled (&self) -> bool;
-    fn enclose (self, w: impl Content<TuiOut>) -> impl Content<TuiOut> {
-        Bsp::b(Fill::XY(Border(self.enabled(), self)), w)
-    }
-    fn enclose2 (self, w: impl Content<TuiOut>) -> impl Content<TuiOut> {
-        Bsp::b(Pad::XY(1, 1, Fill::XY(Border(self.enabled(), self))), w)
-    }
-    fn enclose_bg (self, w: impl Content<TuiOut>) -> impl Content<TuiOut> {
-        Tui::bg(self.style().unwrap().bg.unwrap_or(Color::Reset),
-            Bsp::b(Fill::XY(Border(self.enabled(), self)), w))
-    }
-    const NW: &'static str = "";
-    const N:  &'static str = "";
-    const NE: &'static str = "";
-    const E:  &'static str = "";
-    const SE: &'static str = "";
-    const S:  &'static str = "";
-    const SW: &'static str = "";
-    const W:  &'static str = "";
-
-    const N0: &'static str = "";
-    const S0: &'static str = "";
-    const W0: &'static str = "";
-    const E0: &'static str = "";
-
-    fn border_n (&self) -> &str { Self::N }
-    fn border_s (&self) -> &str { Self::S }
-    fn border_e (&self) -> &str { Self::E }
-    fn border_w (&self) -> &str { Self::W }
-    fn border_nw (&self) -> &str { Self::NW }
-    fn border_ne (&self) -> &str { Self::NE }
-    fn border_sw (&self) -> &str { Self::SW }
-    fn border_se (&self) -> &str { Self::SE }
-    #[inline] fn draw <'a> (
-        &self, to: &mut TuiOut
-    ) -> Usually<()> {
-        if self.enabled() {
-            self.draw_horizontal(to, None)?;
-            self.draw_vertical(to, None)?;
-            self.draw_corners(to, None)?;
-        }
-        Ok(())
-    }
-    #[inline] fn draw_horizontal (
-        &self, to: &mut TuiOut, style: Option<Style>
-    ) -> Usually<[u16;4]> {
-        let area = to.area();
-        let style = style.or_else(||self.style_horizontal());
-        let [x, x2, y, y2] = area.lrtb();
-        for x in x..x2.saturating_sub(1) {
-            to.blit(&Self::N, x, y, style);
-            to.blit(&Self::S, x, y2.saturating_sub(1), style)
-        }
-        Ok(area)
-    }
-    #[inline] fn draw_vertical (
-        &self, to: &mut TuiOut, style: Option<Style>
-    ) -> Usually<[u16;4]> {
-        let area = to.area();
-        let style = style.or_else(||self.style_vertical());
-        let [x, x2, y, y2] = area.lrtb();
-        let h = y2 - y;
-        if h > 1 {
-            for y in y..y2.saturating_sub(1) {
-                to.blit(&Self::W, x, y, style);
-                to.blit(&Self::E, x2.saturating_sub(1), y, style);
-            }
-        } else if h > 0 {
-            to.blit(&Self::W0, x, y, style);
-            to.blit(&Self::E0, x2.saturating_sub(1), y, style);
-        }
-        Ok(area)
-    }
-    #[inline] fn draw_corners (
-        &self, to: &mut TuiOut, style: Option<Style>
-    ) -> Usually<[u16;4]> {
-        let area = to.area();
-        let style = style.or_else(||self.style_corners());
-        let [x, y, width, height] = area.xywh();
-        if width > 1 && height > 1 {
-            to.blit(&Self::NW, x, y, style);
-            to.blit(&Self::NE, x + width - 1, y, style);
-            to.blit(&Self::SW, x, y + height - 1, style);
-            to.blit(&Self::SE, x + width - 1, y + height - 1, style);
-        }
-        Ok(area)
-    }
-    #[inline] fn style            (&self) -> Option<Style> { None }
-    #[inline] fn style_horizontal (&self) -> Option<Style> { self.style() }
-    #[inline] fn style_vertical   (&self) -> Option<Style> { self.style() }
-    #[inline] fn style_corners    (&self) -> Option<Style> { self.style() }
-}
-
-macro_rules! border {
-    ($($T:ident {
-        $nw:literal $n:literal $ne:literal $w:literal $e:literal $sw:literal $s:literal $se:literal
-        $($x:tt)*
-    }),+) => {$(
-        impl BorderStyle for $T {
-            const NW: &'static str = $nw;
-            const N:  &'static str = $n;
-            const NE: &'static str = $ne;
-            const W:  &'static str = $w;
-            const E:  &'static str = $e;
-            const SW: &'static str = $sw;
-            const S:  &'static str = $s;
-            const SE: &'static str = $se;
-            $($x)*
-            fn enabled (&self) -> bool { self.0 }
-        }
-        #[derive(Copy, Clone)] pub struct $T(pub bool, pub Style);
-        impl Layout<TuiOut> for $T {}
-        impl Draw<TuiOut> for $T {
-            fn draw (&self, to: &mut TuiOut) {
-                if self.enabled() { let _ = BorderStyle::draw(self, to); }
-            }
-        }
-    )+}
-}
-
-border! {
-    Square {
-        "┌" "─" "┐"
-        "│"     "│"
-        "└" "─" "┘" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    SquareBold {
-        "┏" "━" "┓"
-        "┃"     "┃"
-        "┗" "━" "┛" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    TabLike {
-        "╭" "─" "╮"
-        "│"     "│"
-        "│" " " "│" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Lozenge {
-        "╭" "─" "╮"
-        "│"     "│"
-        "╰" "─" "╯" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Brace {
-        "╭" "" "╮"
-        "│"    "│"
-        "╰" "" "╯" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    LozengeDotted {
-        "╭" "┅" "╮"
-        "┇"     "┇"
-        "╰" "┅" "╯" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Quarter {
-        "▎" "▔" "🮇"
-        "▎"     "🮇"
-        "▎" "▁" "🮇" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    QuarterV {
-        "▎" "" "🮇"
-        "▎"    "🮇"
-        "▎" "" "🮇" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Chamfer {
-        "🭂" "▔" "🭍"
-        "▎"     "🮇"
-        "🭓" "▁" "🭞" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Corners {
-        "🬆" "" "🬊" // 🬴 🬸
-        ""     ""
-        "🬱" "" "🬵" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    CornersTall {
-        "🭽" "" "🭾"
-        ""     ""
-        "🭼" "" "🭿" fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Outer {
-        "🭽" "▔" "🭾"
-        "▏"     "▕"
-        "🭼" "▁" "🭿"
-        const W0: &'static str = "[";
-        const E0: &'static str = "]";
-        const N0: &'static str = "⎴";
-        const S0: &'static str = "⎵";
-        fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Thick {
-        "▄" "▄" "▄"
-        "█"     "█"
-        "▀" "▀" "▀"
-        fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Rugged {
-        "▄" "▂" "▄"
-        "▐"     "▌"
-        "▀" "🮂" "▀"
-        fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Skinny {
-        "▗" "▄" "▖"
-        "▐"     "▌"
-        "▝" "▀" "▘"
-        fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Brackets {
-        "⎡" "" "⎤"
-        ""     ""
-        "⎣" "" "⎦"
-        const W0: &'static str = "[";
-        const E0: &'static str = "]";
-        const N0: &'static str = "⎴";
-        const S0: &'static str = "⎵";
-        fn style (&self) -> Option<Style> { Some(self.1) }
-    },
-    Reticle {
-        "⎡" "" "⎤"
-        ""     ""
-        "⎣" "" "⎦"
-        const W0: &'static str = "╟";
-        const E0: &'static str = "╢";
-        const N0: &'static str = "┯";
-        const S0: &'static str = "┷";
-        fn style (&self) -> Option<Style> { Some(self.1) }
-    }
-}
diff --git a/tui/src/tui_content/tui_button.rs b/tui/src/tui_content/tui_button.rs
deleted file mode 100644
index d328557..0000000
--- a/tui/src/tui_content/tui_button.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-use crate::{*, Color::*};
-
-pub fn button_2 <'a> (key: impl Content<TuiOut>, label: impl Content<TuiOut>, editing: bool) -> impl Content<TuiOut> {
-    Tui::bold(true, Bsp::e(
-        Tui::fg_bg(Tui::orange(), Tui::g(0), Bsp::e(Tui::fg(Tui::g(0), &"▐"), Bsp::e(key, Tui::fg(Tui::g(96), &"▐")))),
-        When::new(!editing, Tui::fg_bg(Tui::g(255), Tui::g(96), label))))
-}
-
-pub fn button_3 <'a> (
-    key: impl Content<TuiOut>, label: impl Content<TuiOut>, value: impl Content<TuiOut>, editing: bool,
-) -> impl Content<TuiOut> {
-    Tui::bold(true, Bsp::e(
-        Tui::fg_bg(Tui::orange(), Tui::g(0),
-            Bsp::e(Tui::fg(Tui::g(0), &"▐"), Bsp::e(key, Tui::fg(if editing { Tui::g(128) } else { Tui::g(96) }, "▐")))),
-        Bsp::e(
-            When::new(!editing, Bsp::e(Tui::fg_bg(Tui::g(255), Tui::g(96), label), Tui::fg_bg(Tui::g(128), Tui::g(96), &"▐"),)),
-            Bsp::e(Tui::fg_bg(Tui::g(224), Tui::g(128), value), Tui::fg_bg(Tui::g(128), Reset, &"▌"), ))))
-}
diff --git a/tui/src/tui_content/tui_color.rs b/tui/src/tui_content/tui_color.rs
deleted file mode 100644
index 6fb0c8f..0000000
--- a/tui/src/tui_content/tui_color.rs
+++ /dev/null
@@ -1,170 +0,0 @@
-use crate::*;
-use rand::{thread_rng, distributions::uniform::UniformSampler};
-
-impl Tui {
-    pub const fn null     () -> Color { Color::Reset }
-    pub const fn g   (g: u8) -> Color { Color::Rgb(g, g, g) }
-    pub const fn red      () -> Color { Color::Rgb(255,0,  0) }
-    pub const fn orange   () -> Color { Color::Rgb(255,128,0) }
-    pub const fn yellow   () -> Color { Color::Rgb(255,255,0) }
-    pub const fn brown    () -> Color { Color::Rgb(128,255,0) }
-    pub const fn green    () -> Color { Color::Rgb(0,255,0) }
-    pub const fn electric () -> Color { Color::Rgb(0,255,128) }
-    //fn bg0  () -> Color { Color::Rgb(20, 20, 20) }
-    //fn bg   () -> Color { Color::Rgb(28, 35, 25) }
-    //fn border_bg () -> Color { Color::Rgb(40, 50, 30) }
-    //fn border_fg (f: bool) -> Color { if f { Self::bo1() } else { Self::bo2() } }
-    //fn title_fg (f: bool) -> Color { if f { Self::ti1() } else { Self::ti2() } }
-    //fn separator_fg (_: bool) -> Color { Color::Rgb(0, 0, 0) }
-    //fn mode_bg () -> Color { Color::Rgb(150, 160, 90) }
-    //fn mode_fg () -> Color { Color::Rgb(255, 255, 255) }
-    //fn status_bar_bg () -> Color { Color::Rgb(28, 35, 25) }
-    //fn bo1 () -> Color { Color::Rgb(100, 110, 40) }
-    //fn bo2 () -> Color { Color::Rgb(70, 80, 50) }
-    //fn ti1 () -> Color { Color::Rgb(150, 160, 90) }
-    //fn ti2 () -> Color { Color::Rgb(120, 130, 100) }
-}
-
-pub trait HasColor { fn color (&self) -> ItemColor; }
-
-#[macro_export] macro_rules! has_color {
-    (|$self:ident:$Struct:ident$(<$($L:lifetime),*$($T:ident$(:$U:path)?),*>)?|$cb:expr) => {
-        impl $(<$($L),*$($T $(: $U)?),*>)? HasColor for $Struct $(<$($L),*$($T),*>)? {
-            fn color (&$self) -> ItemColor { $cb }
-        }
-    }
-}
-
-/// A color in OKHSL and RGB representations.
-#[derive(Debug, Default, Copy, Clone, PartialEq)] pub struct ItemColor {
-    pub okhsl: Okhsl<f32>,
-    pub rgb:   Color,
-}
-from!(ItemColor: |okhsl: Okhsl<f32>|Self { okhsl, rgb: okhsl_to_rgb(okhsl) });
-from!(ItemColor: |rgb: Color|Self { rgb, okhsl: rgb_to_okhsl(rgb) });
-pub fn okhsl_to_rgb (color: Okhsl<f32>) -> Color {
-    let Srgb { red, green, blue, .. }: Srgb<f32> = Srgb::from_color_unclamped(color);
-    Color::Rgb((red   * 255.0) as u8, (green * 255.0) as u8, (blue  * 255.0) as u8,)
-}
-pub fn rgb_to_okhsl (color: Color) -> Okhsl<f32> {
-    if let Color::Rgb(r, g, b) = color {
-        Okhsl::from_color(Srgb::new(r as f32 / 255.0, g as f32 / 255.0, b as f32 / 255.0))
-    } else {
-        unreachable!("only Color::Rgb is supported")
-    }
-}
-
-// A single color within item theme parameters, in OKHSL and RGB representations.
-impl ItemColor {
-    pub const fn from_rgb (rgb: Color) -> Self {
-        Self { rgb, okhsl: Okhsl::new_const(OklabHue::new(0.0), 0.0, 0.0) }
-    }
-    pub const fn from_okhsl (okhsl: Okhsl<f32>) -> Self {
-        Self { rgb: Color::Rgb(0, 0, 0), okhsl }
-    }
-    pub fn random () -> Self {
-        let mut rng = thread_rng();
-        let lo = Okhsl::new(-180.0, 0.01, 0.25);
-        let hi = Okhsl::new( 180.0, 0.9,  0.5);
-        UniformOkhsl::new(lo, hi).sample(&mut rng).into()
-    }
-    pub fn random_dark () -> Self {
-        let mut rng = thread_rng();
-        let lo = Okhsl::new(-180.0, 0.025, 0.075);
-        let hi = Okhsl::new( 180.0, 0.5,   0.150);
-        UniformOkhsl::new(lo, hi).sample(&mut rng).into()
-    }
-    pub fn random_near (color: Self, distance: f32) -> Self {
-        color.mix(Self::random(), distance)
-    }
-    pub fn mix (&self, other: Self, distance: f32) -> Self {
-        if distance > 1.0 { panic!("color mixing takes distance between 0.0 and 1.0"); }
-        self.okhsl.mix(other.okhsl, distance).into()
-    }
-}
-
-/// A color in OKHSL and RGB with lighter and darker variants.
-#[derive(Debug, Default, Copy, Clone, PartialEq)] pub struct ItemTheme {
-    pub base:     ItemColor,
-    pub light:    ItemColor,
-    pub lighter:  ItemColor,
-    pub lightest: ItemColor,
-    pub dark:     ItemColor,
-    pub darker:   ItemColor,
-    pub darkest:  ItemColor,
-}
-
-from!(ItemTheme: |base: Color|    Self::from_tui_color(base));
-from!(ItemTheme: |base: ItemColor|Self::from_item_color(base));
-impl ItemTheme {
-    pub const G: [Self;256] = {
-        let mut builder = konst::array::ArrayBuilder::new();
-        while !builder.is_full() {
-            let index    = builder.len() as u8;
-            let light    = (index as f64 * 1.15) as u8;
-            let lighter  = (index as f64 * 1.7) as u8;
-            let lightest = (index as f64 * 1.85) as u8;
-            let dark     = (index as f64 * 0.9) as u8;
-            let darker   = (index as f64 * 0.6) as u8;
-            let darkest  = (index as f64 * 0.3) as u8;
-            builder.push(ItemTheme {
-                base:     ItemColor::from_rgb(Color::Rgb(index,    index,    index     )),
-                light:    ItemColor::from_rgb(Color::Rgb(light,    light,    light,    )),
-                lighter:  ItemColor::from_rgb(Color::Rgb(lighter,  lighter,  lighter,  )),
-                lightest: ItemColor::from_rgb(Color::Rgb(lightest, lightest, lightest, )),
-                dark:     ItemColor::from_rgb(Color::Rgb(dark,     dark,     dark,     )),
-                darker:   ItemColor::from_rgb(Color::Rgb(darker,   darker,   darker,   )),
-                darkest:  ItemColor::from_rgb(Color::Rgb(darkest,  darkest,  darkest,  )),
-            });
-        }
-        builder.build()
-    };
-    pub fn random () -> Self { ItemColor::random().into() }
-    pub fn random_near (color: Self, distance: f32) -> Self {
-        color.base.mix(ItemColor::random(), distance).into()
-    }
-    pub const G00: Self = {
-        let color: ItemColor = ItemColor {
-            okhsl: Okhsl { hue: OklabHue::new(0.0), lightness: 0.0, saturation: 0.0 },
-            rgb: Color::Rgb(0, 0, 0)
-        };
-        Self {
-            base:     color,
-            light:    color,
-            lighter:  color,
-            lightest: color,
-            dark:     color,
-            darker:   color,
-            darkest:  color,
-        }
-    };
-    pub fn from_tui_color (base: Color) -> Self {
-        Self::from_item_color(ItemColor::from_rgb(base))
-    }
-    pub fn from_item_color (base: ItemColor) -> Self {
-        let mut light      = base.okhsl;
-        light.lightness    = (light.lightness    * 1.3).min(1.0);
-        let mut lighter    = light;
-        lighter.lightness  = (lighter.lightness  * 1.3).min(1.0);
-        let mut lightest   = base.okhsl;
-        lightest.lightness = 0.95;
-        let mut dark       = base.okhsl;
-        dark.lightness     = (dark.lightness     * 0.75).max(0.0);
-        dark.saturation    = (dark.saturation    * 0.75).max(0.0);
-        let mut darker     = dark;
-        darker.lightness   = (darker.lightness   * 0.66).max(0.0);
-        darker.saturation  = (darker.saturation  * 0.66).max(0.0);
-        let mut darkest    = darker;
-        darkest.lightness  = 0.1;
-        darkest.saturation = (darkest.saturation * 0.50).max(0.0);
-        Self {
-            base,
-            light:    light.into(),
-            lighter:  lighter.into(),
-            lightest: lightest.into(),
-            dark:     dark.into(),
-            darker:   darker.into(),
-            darkest:  darkest.into(),
-        }
-    }
-}
diff --git a/tui/src/tui_content/tui_error.rs b/tui/src/tui_content/tui_error.rs
deleted file mode 100644
index e4d4549..0000000
--- a/tui/src/tui_content/tui_error.rs
+++ /dev/null
@@ -1,29 +0,0 @@
-use crate::*;
-use ratatui::style::Stylize;
-
-// Thunks can be natural error boundaries!
-pub struct ErrorBoundary<O: Out, T: Draw<O>>(
-    std::marker::PhantomData<O>, Perhaps<T>
-);
-
-impl<O: Out, T: Draw<O>> ErrorBoundary<O, T> {
-    pub fn new (content: Perhaps<T>) -> Self {
-        Self(Default::default(), content)
-    }
-}
-
-impl<T: Draw<TuiOut>> Draw<TuiOut> for ErrorBoundary<TuiOut, T> {
-    fn draw (&self, to: &mut TuiOut) {
-        match self.1.as_ref() {
-            Ok(Some(content)) => content.draw(to),
-            Ok(None) => to.blit(&"empty?", 0, 0, Some(Style::default().yellow())),
-            Err(e) => {
-                let err_fg = Color::Rgb(255,224,244);
-                let err_bg = Color::Rgb(96,24,24);
-                let title  = Bsp::e(Tui::bold(true, "oops. "), "rendering failed.");
-                let error  = Bsp::e("\"why?\" ", Tui::bold(true, format!("{e}")));
-                to.place(&Tui::fg_bg(err_fg, err_bg, Bsp::s(title, error)))
-            }
-        }
-    }
-}
diff --git a/tui/src/tui_content/tui_number.rs b/tui/src/tui_content/tui_number.rs
deleted file mode 100644
index 9278af5..0000000
--- a/tui/src/tui_content/tui_number.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-use crate::*;
-
-impl Draw<TuiOut> for u64 {
-    fn draw (&self, _to: &mut TuiOut) {
-        todo!()
-    }
-}
-
-impl Draw<TuiOut> for f64 {
-    fn draw (&self, _to: &mut TuiOut) {
-        todo!()
-    }
-}
diff --git a/tui/src/tui_content/tui_phat.rs b/tui/src/tui_content/tui_phat.rs
deleted file mode 100644
index df592f0..0000000
--- a/tui/src/tui_content/tui_phat.rs
+++ /dev/null
@@ -1,29 +0,0 @@
-use crate::*;
-
-/// A cell that takes up 3 rows on its own,
-/// but stacks, giving (N+1)*2 rows per N cells.
-pub struct Phat<T> {
-    pub width:   u16,
-    pub height:  u16,
-    pub content: T,
-    pub colors:  [Color;4],
-}
-
-impl<T> Phat<T> {
-    pub const LO: &'static str = "▄";
-    pub const HI: &'static str = "▀";
-    /// A phat line
-    pub fn lo (fg: Color, bg: Color) -> impl Content<TuiOut> { Fixed::Y(1, Tui::fg_bg(fg, bg, RepeatH(Self::LO))) }
-    /// A phat line
-    pub fn hi (fg: Color, bg: Color) -> impl Content<TuiOut> { Fixed::Y(1, Tui::fg_bg(fg, bg, RepeatH(Self::HI))) }
-}
-
-impl<T: Content<TuiOut>> HasContent<TuiOut> for Phat<T> {
-    fn content (&self) -> impl Content<TuiOut> {
-        let [fg, bg, hi, lo] = self.colors;
-        let top = Fixed::Y(1, Self::lo(bg, hi));
-        let low = Fixed::Y(1, Self::hi(bg, lo));
-        let content = Tui::fg_bg(fg, bg, &self.content);
-        Min::XY(self.width, self.height, Bsp::s(top, Bsp::n(low, Fill::XY(content))))
-    }
-}
diff --git a/tui/src/tui_content/tui_repeat.rs b/tui/src/tui_content/tui_repeat.rs
deleted file mode 100644
index 3f6b1c3..0000000
--- a/tui/src/tui_content/tui_repeat.rs
+++ /dev/null
@@ -1,44 +0,0 @@
-use crate::*;
-use ratatui::prelude::Position;
-
-pub struct Repeat<'a>(pub &'a str);
-impl Draw<TuiOut> for Repeat<'_> {
-    fn draw (&self, to: &mut TuiOut) {
-        let [x, y, w, h] = to.area().xywh();
-        let a = self.0.len();
-        for (_v, y) in (y..y+h).enumerate() {
-            for (u, x) in (x..x+w).enumerate() {
-                if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
-                    let u = u % a;
-                    cell.set_symbol(&self.0[u..u+1]);
-                }
-            }
-        }
-    }
-}
-
-pub struct RepeatV<'a>(pub &'a str);
-impl Layout<TuiOut> for RepeatV<'_> {}
-impl Draw<TuiOut> for RepeatV<'_> {
-    fn draw (&self, to: &mut TuiOut) {
-        let [x, y, _w, h] = to.area().xywh();
-        for y in y..y+h {
-            if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
-                cell.set_symbol(&self.0);
-            }
-        }
-    }
-}
-
-pub struct RepeatH<'a>(pub &'a str);
-impl Layout<TuiOut> for RepeatH<'_> {}
-impl Draw<TuiOut> for RepeatH<'_> {
-    fn draw (&self, to: &mut TuiOut) {
-        let [x, y, w, _h] = to.area().xywh();
-        for x in x..x+w {
-            if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
-                cell.set_symbol(&self.0);
-            }
-        }
-    }
-}
diff --git a/tui/src/tui_content/tui_scroll.rs b/tui/src/tui_content/tui_scroll.rs
deleted file mode 100644
index ec8faf5..0000000
--- a/tui/src/tui_content/tui_scroll.rs
+++ /dev/null
@@ -1,80 +0,0 @@
-use crate::*;
-use ratatui::{prelude::Position, style::Color::*};
-
-pub struct ScrollbarV {
-    pub offset: usize,
-    pub length: usize,
-    pub total:  usize,
-}
-
-pub struct ScrollbarH {
-    pub offset: usize,
-    pub length: usize,
-    pub total:  usize,
-}
-
-impl ScrollbarV {
-    const ICON_DEC: &[char] = &['▲'];
-    const ICON_INC: &[char] = &['▼'];
-}
-
-impl ScrollbarH {
-    const ICON_DEC: &[char] = &[' ', '🞀', ' '];
-    const ICON_INC: &[char] = &[' ', '🞂', ' '];
-}
-
-impl Draw<TuiOut> for ScrollbarV {
-    fn draw (&self, to: &mut TuiOut) {
-        let [x, y1, _w, h] = to.area().xywh();
-        let y2 = y1 + h;
-        for (i, y) in (y1..=y2).enumerate() {
-            if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
-                if (i as usize) < (Self::ICON_DEC.len()) {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Rgb(0, 0, 0));
-                    cell.set_char(Self::ICON_DEC[i as usize]);
-                } else if (i as usize) > (h as usize - Self::ICON_INC.len()) {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Rgb(0, 0, 0));
-                    cell.set_char(Self::ICON_INC[h as usize - i]);
-                } else if false {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Reset);
-                    cell.set_char('‖'); // ━
-                } else {
-                    cell.set_fg(Rgb(0, 0, 0));
-                    cell.set_bg(Reset);
-                    cell.set_char('╎'); // ━
-                }
-            }
-        }
-    }
-}
-
-impl Draw<TuiOut> for ScrollbarH {
-    fn draw (&self, to: &mut TuiOut) {
-        let [x1, y, w, _h] = to.area().xywh();
-        let x2 = x1 + w;
-        for (i, x) in (x1..=x2).enumerate() {
-            if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
-                if i < (Self::ICON_DEC.len()) {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Rgb(0, 0, 0));
-                    cell.set_char(Self::ICON_DEC[i as usize]);
-                } else if i > (w as usize - Self::ICON_INC.len()) {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Rgb(0, 0, 0));
-                    cell.set_char(Self::ICON_INC[w as usize - i]);
-                } else if false {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Reset);
-                    cell.set_char('━');
-                } else {
-                    cell.set_fg(Rgb(0, 0, 0));
-                    cell.set_bg(Reset);
-                    cell.set_char('╌');
-                }
-            }
-        }
-    }
-}
diff --git a/tui/src/tui_content/tui_string.rs b/tui/src/tui_content/tui_string.rs
deleted file mode 100644
index eae8982..0000000
--- a/tui/src/tui_content/tui_string.rs
+++ /dev/null
@@ -1,105 +0,0 @@
-use crate::*;
-use crate::ratatui::prelude::Position;
-use unicode_width::{UnicodeWidthStr, UnicodeWidthChar};
-
-impl Draw<TuiOut> for &str {
-    fn draw (&self, to: &mut TuiOut) {
-        let [x, y, w, ..] = self.layout(to.area());
-        to.text(&self, x, y, w)
-    }
-}
-impl Draw<TuiOut> for String {
-    fn draw (&self, to: &mut TuiOut) {
-        self.as_str().draw(to)
-    }
-}
-impl Draw<TuiOut> for Arc<str> {
-    fn draw (&self, to: &mut TuiOut) { self.as_ref().draw(to) }
-}
-
-impl Layout<TuiOut> for &str {
-    fn layout (&self, to: [u16;4]) -> [u16;4] { to.center_xy([width_chars_max(to.w(), self), 1]) }
-}
-impl Layout<TuiOut> for String {
-    fn layout (&self, to: [u16;4]) -> [u16;4] {
-        self.as_str().layout(to)
-    }
-}
-impl Layout<TuiOut> for Arc<str> {
-    fn layout (&self, to: [u16;4]) -> [u16;4] {
-        self.as_ref().layout(to)
-    }
-}
-
-fn width_chars_max (max: u16, text: impl AsRef<str>) -> u16 {
-    let mut width: u16 = 0;
-    let mut chars = text.as_ref().chars();
-    while let Some(c) = chars.next() {
-        width += c.width().unwrap_or(0) as u16;
-        if width > max {
-            break
-        }
-    }
-    return width
-}
-
-/// Trim string with [unicode_width].
-pub fn trim_string (max_width: usize, input: impl AsRef<str>) -> String {
-    let input = input.as_ref();
-    let mut output = Vec::with_capacity(input.len());
-    let mut width: usize = 1;
-    let mut chars = input.chars();
-    while let Some(c) = chars.next() {
-        if width > max_width {
-            break
-        }
-        output.push(c);
-        width += c.width().unwrap_or(0);
-    }
-    return output.into_iter().collect()
-}
-
-/// Displays an owned [str]-like with fixed maximum width.
-///
-/// Width is computed using [unicode_width].
-pub struct TrimString<T: AsRef<str>>(pub u16, pub T);
-
-impl<'a, T: AsRef<str>> TrimString<T> {
-    fn as_ref (&self) -> TrimStringRef<'_, T> { TrimStringRef(self.0, &self.1) }
-}
-impl<'a, T: AsRef<str>> Draw<TuiOut> for TrimString<T> {
-    fn draw (&self, to: &mut TuiOut) { Draw::draw(&self.as_ref(), to) }
-}
-impl<'a, T: AsRef<str>> Layout<TuiOut> for TrimString<T> {
-    fn layout (&self, to: [u16; 4]) -> [u16;4] { Layout::layout(&self.as_ref(), to) }
-}
-
-/// Displays a borrowed [str]-like with fixed maximum width
-///
-/// Width is computed using [unicode_width].
-pub struct TrimStringRef<'a, T: AsRef<str>>(pub u16, pub &'a T);
-
-impl<'a, T: AsRef<str>> Layout<TuiOut> for TrimStringRef<'a, T> {
-    fn layout (&self, to: [u16; 4]) -> [u16;4] {
-        [to.x(), to.y(), to.w().min(self.0).min(self.1.as_ref().width() as u16), to.h()]
-    }
-}
-impl<T: AsRef<str>> Draw<TuiOut> for TrimStringRef<'_, T> {
-    fn draw (&self, target: &mut TuiOut) {
-        let area = target.area();
-        let mut width: u16 = 1;
-        let mut chars = self.1.as_ref().chars();
-        while let Some(c) = chars.next() {
-            if width > self.0 || width > area.w() {
-                break
-            }
-            if let Some(cell) = target.buffer.cell_mut(Position {
-                x: area.x() + width - 1,
-                y: area.y()
-            }) {
-                cell.set_char(c);
-            }
-            width += c.width().unwrap_or(0) as u16;
-        }
-    }
-}
diff --git a/tui/src/tui_content/tui_tryptich.rs b/tui/src/tui_content/tui_tryptich.rs
deleted file mode 100644
index ba869ca..0000000
--- a/tui/src/tui_content/tui_tryptich.rs
+++ /dev/null
@@ -1,28 +0,0 @@
-use crate::*;
-
-impl<
-    A: Content<TuiOut>,
-    B: Content<TuiOut>,
-    C: Content<TuiOut>,
-> HasContent<TuiOut> for Tryptich<A, B, C> {
-    fn content (&self) -> impl Content<TuiOut> {
-        let Self { top, h, left: (w_a, ref a), middle: (w_b, ref b), right: (w_c, ref c) } = *self;
-        Fixed::Y(h, if top {
-            Bsp::a(
-                Fill::X(Align::n(Fixed::X(w_b, Align::x(Tui::bg(Color::Reset, b))))),
-                Bsp::a(
-                    Fill::X(Align::nw(Fixed::X(w_a, Tui::bg(Color::Reset, a)))),
-                    Fill::X(Align::ne(Fixed::X(w_c, Tui::bg(Color::Reset, c)))),
-                ),
-            )
-        } else {
-            Bsp::a(
-                Fill::XY(Align::c(Fixed::X(w_b, Align::x(Tui::bg(Color::Reset, b))))),
-                Bsp::a(
-                    Fill::XY(Align::w(Fixed::X(w_a, Tui::bg(Color::Reset, a)))),
-                    Fill::XY(Align::e(Fixed::X(w_c, Tui::bg(Color::Reset, c)))),
-                ),
-            )
-        })
-    }
-}
diff --git a/tui/src/tui_engine.rs b/tui/src/tui_engine.rs
deleted file mode 100644
index 1c53261..0000000
--- a/tui/src/tui_engine.rs
+++ /dev/null
@@ -1,148 +0,0 @@
-use crate::*;
-use std::time::Duration;
-
-mod tui_buffer; pub use self::tui_buffer::*;
-mod tui_input;  pub use self::tui_input::*;
-mod tui_event;  pub use self::tui_event::*;
-mod tui_output; pub use self::tui_output::*;
-mod tui_perf;   pub use self::tui_perf::*;
-
-// The `Tui` struct (the *engine*) implements the
-// `tengri_input::Input` and `tengri_output::Out` traits.
-
-// At launch, the `Tui` engine spawns two threads, the render thread and the input thread.
-// the application may further spawn other threads. All threads communicate using shared ownership:
-// `Arc<RwLock<T>>` and `Arc<AtomicT>`. Thus, at launch the engine and application instances are expected to be wrapped in `Arc<RwLock>`.
-pub struct Tui {
-    pub exited:  Arc<AtomicBool>,
-    pub backend: CrosstermBackend<Stdout>,
-    pub buffer:  Buffer,
-    pub area:    [u16;4],
-    pub perf:    PerfModel,
-}
-
-impl Tui {
-    /// Construct a new TUI engine and wrap it for shared ownership.
-    pub fn new () -> Usually<Arc<RwLock<Self>>> {
-        let backend = CrosstermBackend::new(stdout());
-        let Size { width, height } = backend.size()?;
-        Ok(Arc::new(RwLock::new(Self {
-            exited:  Arc::new(AtomicBool::new(false)),
-            buffer:  Buffer::empty(Rect { x: 0, y: 0, width, height }),
-            area:    [0, 0, width, height],
-            backend,
-            perf: Default::default(),
-        })))
-    }
-    /// True if done
-    pub fn exited (&self) -> bool {
-        self.exited.fetch_and(true, Relaxed)
-    }
-    /// Prepare before run
-    pub fn setup (&mut self) -> Usually<()> {
-        let better_panic_handler = Settings::auto().verbosity(Verbosity::Full).create_panic_handler();
-        std::panic::set_hook(Box::new(move |info: &std::panic::PanicHookInfo|{
-            stdout().execute(LeaveAlternateScreen).unwrap();
-            CrosstermBackend::new(stdout()).show_cursor().unwrap();
-            disable_raw_mode().unwrap();
-            better_panic_handler(info);
-        }));
-        stdout().execute(EnterAlternateScreen)?;
-        self.backend.hide_cursor()?;
-        enable_raw_mode().map_err(Into::into)
-    }
-    /// Update the display buffer.
-    pub fn flip (&mut self, mut buffer: Buffer, size: ratatui::prelude::Rect) -> Buffer {
-        if self.buffer.area != size {
-            self.backend.clear_region(ClearType::All).unwrap();
-            self.buffer.resize(size);
-            self.buffer.reset();
-        }
-        let updates = self.buffer.diff(&buffer);
-        self.backend.draw(updates.into_iter()).expect("failed to render");
-        self.backend.flush().expect("failed to flush output buffer");
-        std::mem::swap(&mut self.buffer, &mut buffer);
-        buffer.reset();
-        buffer
-    }
-    /// Clean up after run
-    pub fn teardown (&mut self) -> Usually<()> {
-        stdout().execute(LeaveAlternateScreen)?;
-        self.backend.show_cursor()?;
-        disable_raw_mode().map_err(Into::into)
-    }
-}
-
-pub trait TuiDraw    = Draw<TuiOut>;
-pub trait TuiLayout  = Layout<TuiOut>;
-pub trait TuiContent = Content<TuiOut>;
-pub trait TuiHandle  = Handle<TuiIn>;
-pub trait TuiWidget  = TuiDraw + TuiHandle;
-
-pub trait TuiRun<T: TuiWidget + 'static> {
-    /// Run an app in the main loop.
-    fn run (&self, state: &Arc<RwLock<T>>) -> Usually<()>;
-}
-
-impl<T: TuiWidget + Send + Sync + 'static> TuiRun<T> for Arc<RwLock<Tui>> {
-    fn run (&self, state: &Arc<RwLock<T>>) -> Usually<()> {
-        let _input_thread = TuiIn::run_input(self, state, Duration::from_millis(100));
-        self.write().unwrap().setup()?;
-        let render_thread = TuiOut::run_output(self, state, Duration::from_millis(10))?;
-        match render_thread.join() {
-            Ok(result) => {
-                self.write().unwrap().teardown()?;
-                println!("\n\rRan successfully: {result:?}\n\r");
-            },
-            Err(error) => {
-                self.write().unwrap().teardown()?;
-                panic!("\n\rDraw thread failed: error={error:?}.\n\r")
-            },
-        }
-        Ok(())
-    }
-}
-
-#[cfg(feature = "dsl")] 
-pub fn evaluate_output_expression_tui <'a, S> (
-    state: &S, output: &mut TuiOut, expr: impl Expression + 'a
-) -> Usually<bool> where
-    S: View<TuiOut, ()>
-        + for<'b>Namespace<'b, bool>
-        + for<'b>Namespace<'b, u16>
-        + for<'b>Namespace<'b, Color>
-{
-    // See `tengri_output::evaluate_output_expression`
-    let head = expr.head()?;
-    let mut frags = head.src()?.unwrap_or_default().split("/");
-    let args  = expr.tail();
-    let arg0  = args.head();
-    let tail0 = args.tail();
-    let arg1  = tail0.head();
-    let tail1 = tail0.tail();
-    let _arg2 = tail1.head();
-    match frags.next() {
-
-        Some("text") => if let Some(src) = args?.src()? { output.place(&src) },
-
-        Some("fg") => {
-            let arg0 = arg0?.expect("fg: expected arg 0 (color)");
-            output.place(&Tui::fg(
-                Namespace::<Color>::resolve(state, arg0)?.unwrap_or_else(||panic!("fg: {arg0:?}: not a color")),
-                Thunk::new(move|output: &mut TuiOut|state.view(output, &arg1).unwrap()),
-            ))
-        },
-
-        Some("bg") => {
-            let arg0 = arg0?.expect("bg: expected arg 0 (color)");
-            output.place(&Tui::bg(
-                Namespace::<Color>::resolve(state, arg0)?.unwrap_or_else(||panic!("bg: {arg0:?}: not a color")),
-                Thunk::new(move|output: &mut TuiOut|state.view(output, &arg1).unwrap()),
-            ))
-        },
-
-        _ => return Ok(false)
-
-    };
-    Ok(true)
-}
diff --git a/tui/src/tui_engine/tui_buffer.rs b/tui/src/tui_engine/tui_buffer.rs
deleted file mode 100644
index 6f21662..0000000
--- a/tui/src/tui_engine/tui_buffer.rs
+++ /dev/null
@@ -1,44 +0,0 @@
-use crate::*;
-
-pub fn buffer_update (buf: &mut Buffer, area: [u16;4], callback: &impl Fn(&mut Cell, u16, u16)) {
-    for row in 0..area.h() {
-        let y = area.y() + row;
-        for col in 0..area.w() {
-            let x = area.x() + col;
-            if x < buf.area.width && y < buf.area.height {
-                if let Some(cell) = buf.cell_mut(ratatui::prelude::Position { x, y }) {
-                    callback(cell, col, row);
-                }
-            }
-        }
-    }
-}
-
-#[derive(Default)] pub struct BigBuffer {
-    pub width:   usize,
-    pub height:  usize,
-    pub content: Vec<Cell>
-}
-
-impl_debug!(BigBuffer |self, f| {
-    write!(f, "[BB {}x{} ({})]", self.width, self.height, self.content.len())
-});
-
-impl BigBuffer {
-    pub fn new (width: usize, height: usize) -> Self {
-        Self { width, height, content: vec![Cell::default(); width*height] }
-    }
-    pub fn get (&self, x: usize, y: usize) -> Option<&Cell> {
-        let i = self.index_of(x, y);
-        self.content.get(i)
-    }
-    pub fn get_mut (&mut self, x: usize, y: usize) -> Option<&mut Cell> {
-        let i = self.index_of(x, y);
-        self.content.get_mut(i)
-    }
-    pub fn index_of (&self, x: usize, y: usize) -> usize {
-        y * self.width + x
-    }
-}
-
-from!(BigBuffer: |size:(usize, usize)| Self::new(size.0, size.1));
diff --git a/tui/src/tui_engine/tui_event.rs b/tui/src/tui_engine/tui_event.rs
deleted file mode 100644
index ead67fc..0000000
--- a/tui/src/tui_engine/tui_event.rs
+++ /dev/null
@@ -1,148 +0,0 @@
-use crate::*;
-#[derive(Debug, Clone, Eq, PartialEq, PartialOrd)] pub struct TuiEvent(pub Event);
-impl Ord for TuiEvent {
-    fn cmp (&self, other: &Self) -> std::cmp::Ordering {
-        self.partial_cmp(other)
-            .unwrap_or_else(||format!("{:?}", self).cmp(&format!("{other:?}"))) // FIXME perf
-    }
-}
-impl TuiEvent {
-    pub fn from_crossterm (event: Event) -> Self {
-        Self(event)
-    }
-    #[cfg(feature = "dsl")]
-    pub fn from_dsl (dsl: impl Language) -> Perhaps<Self> {
-        Ok(TuiKey::from_dsl(dsl)?.to_crossterm().map(Self))
-    }
-}
-pub struct TuiKey(Option<KeyCode>, KeyModifiers);
-impl TuiKey {
-    const SPLIT: char = '/';
-    #[cfg(feature = "dsl")]
-    pub fn from_dsl (dsl: impl Language) -> Usually<Self> {
-        if let Some(word) = dsl.word()? {
-            let word = word.trim();
-            Ok(if word == ":char" {
-                Self(None, KeyModifiers::NONE)
-            } else if word.chars().nth(0) == Some('@') {
-                let mut key       = None;
-                let mut modifiers = KeyModifiers::NONE;
-                let mut tokens    = word[1..].split(Self::SPLIT).peekable();
-                while let Some(token) = tokens.next() {
-                    if tokens.peek().is_some() {
-                        match token {
-                            "ctrl"  | "Ctrl"  | "c" | "C" => modifiers |= KeyModifiers::CONTROL,
-                            "alt"   | "Alt"   | "m" | "M" => modifiers |= KeyModifiers::ALT,
-                            "shift" | "Shift" | "s" | "S" => {
-                                modifiers |= KeyModifiers::SHIFT;
-                                // + TODO normalize character case, BackTab, etc.
-                            },
-                            _ => panic!("unknown modifier {token}"),
-                        }
-                    } else {
-                        key = if token.len() == 1 {
-                            Some(KeyCode::Char(token.chars().next().unwrap()))
-                        } else {
-                            Some(named_key(token).unwrap_or_else(||panic!("unknown character {token}")))
-                        }
-                    }
-                }
-                Self(key, modifiers)
-            } else {
-                return Err(format!("TuiKey: unexpected: {word}").into())
-            })
-        } else {
-            return Err(format!("TuiKey: unspecified").into())
-        }
-    }
-    pub fn to_crossterm (&self) -> Option<Event> {
-        self.0.map(|code|Event::Key(KeyEvent {
-            code,
-            modifiers: self.1,
-            kind:  KeyEventKind::Press,
-            state: KeyEventState::NONE,
-        }))
-    }
-}
-pub fn named_key (token: &str) -> Option<KeyCode> {
-    use KeyCode::*;
-    Some(match token {
-        "up"                => Up,
-        "down"              => Down,
-        "left"              => Left,
-        "right"             => Right,
-        "esc"    | "escape" => Esc,
-        "enter"  | "return" => Enter,
-        "delete" | "del"    => Delete,
-        "backspace"         => Backspace,
-        "tab"               => Tab,
-        "space"             => Char(' '),
-        "comma"             => Char(','),
-        "period"            => Char('.'),
-        "plus"              => Char('+'),
-        "minus" | "dash"    => Char('-'),
-        "equal" | "equals"  => Char('='),
-        "underscore"        => Char('_'),
-        "backtick"          => Char('`'),
-        "lt"                => Char('<'),
-        "gt"                => Char('>'),
-        "cbopen"  | "openbrace"  => Char('{'),
-        "cbclose" | "closebrace" => Char('}'),
-        "bropen"  | "openbracket"  => Char('['),
-        "brclose" | "closebracket" => Char(']'),
-        "pgup" | "pageup"   => PageUp,
-        "pgdn" | "pagedown" => PageDown, 
-        "f1"                => F(1),
-        "f2"                => F(2),
-        "f3"                => F(3),
-        "f4"                => F(4),
-        "f5"                => F(5),
-        "f6"                => F(6),
-        "f7"                => F(7),
-        "f8"                => F(8),
-        "f9"                => F(9),
-        "f10"               => F(10),
-        "f11"               => F(11),
-        "f12"               => F(12),
-        _ => return None,
-    })
-}
-        //let token = token.as_ref();
-        //if token.len() < 2 {
-            //Self { valid: false, key: None, mods: KeyModifiers::NONE }
-        //} else if token.chars().next() != Some('@') {
-            //Self { valid: false, key: None, mods: KeyModifiers::NONE }
-        //} else {
-            //Self { valid: true, key: None, mods: KeyModifiers::NONE }.next(&token[1..])
-        //}
-    //}
-    //pub fn build (self) -> Option<Event> {
-        //if self.valid && self.key.is_some() {
-            //Some(Event::Key(KeyEvent::new(self.key.unwrap(), self.mods)))
-        //} else {
-            //None
-        //}
-    //}
-    //fn next (mut self, token: &str) -> Self {
-        //let mut tokens = token.split('-').peekable();
-        //while let Some(token) = tokens.next() {
-            //if tokens.peek().is_some() {
-                //match token {
-                    //"ctrl"  | "Ctrl"  | "c" | "C" => self.mods |= KeyModifiers::CONTROL,
-                    //"alt"   | "Alt"   | "m" | "M" => self.mods |= KeyModifiers::ALT,
-                    //"shift" | "Shift" | "s" | "S" => {
-                        //self.mods |= KeyModifiers::SHIFT;
-                        //// + TODO normalize character case, BackTab, etc.
-                    //},
-                    //_ => panic!("unknown modifier {token}"),
-                //}
-            //} else {
-                //self.key = if token.len() == 1 {
-                    //Some(KeyCode::Char(token.chars().next().unwrap()))
-                //} else {
-                    //Some(Self::named_key(token).unwrap_or_else(||panic!("unknown character {token}")))
-                //}
-            //}
-        //}
-        //self
-    //}
diff --git a/tui/src/tui_engine/tui_input.rs b/tui/src/tui_engine/tui_input.rs
deleted file mode 100644
index f42da7c..0000000
--- a/tui/src/tui_engine/tui_input.rs
+++ /dev/null
@@ -1,55 +0,0 @@
-use crate::*;
-use std::time::Duration;
-use std::thread::{spawn, JoinHandle};
-use crossterm::event::{Event, poll, read};
-
-#[derive(Debug, Clone)]
-pub struct TuiIn {
-    /// Exit flag
-    pub exited: Arc<AtomicBool>,
-    /// Input event
-    pub event: TuiEvent,
-}
-impl Input for TuiIn {
-    type Event   = TuiEvent;
-    type Handled = bool;
-    fn event   (&self) -> &TuiEvent { &self.event }
-    fn is_done (&self) -> bool { self.exited.fetch_and(true, Relaxed) }
-    fn done    (&self) { self.exited.store(true, Relaxed); }
-}
-impl TuiIn {
-    /// Spawn the input thread.
-    pub fn run_input <T: Handle<TuiIn> + Send + Sync + 'static> (
-        engine: &Arc<RwLock<Tui>>,
-        state:  &Arc<RwLock<T>>,
-        timer:  Duration
-    ) -> JoinHandle<()> {
-        let exited = engine.read().unwrap().exited.clone();
-        let state  = state.clone();
-        spawn(move || loop {
-            if exited.fetch_and(true, Relaxed) {
-                break
-            }
-            if poll(timer).is_ok() {
-                let event = read().unwrap();
-                match event {
-                    Event::Key(KeyEvent {
-                        code:      KeyCode::Char('c'),
-                        modifiers: KeyModifiers::CONTROL,
-                        kind:      KeyEventKind::Press,
-                        state:     KeyEventState::NONE
-                    }) => {
-                        exited.store(true, Relaxed);
-                    },
-                    _ => {
-                        let exited = exited.clone();
-                        let event  = TuiEvent::from_crossterm(event);
-                        if let Err(e) = state.write().unwrap().handle(&TuiIn { exited, event }) {
-                            panic!("{e}")
-                        }
-                    }
-                }
-            }
-        })
-    }
-}
diff --git a/tui/src/tui_engine/tui_output.rs b/tui/src/tui_engine/tui_output.rs
deleted file mode 100644
index de32046..0000000
--- a/tui/src/tui_engine/tui_output.rs
+++ /dev/null
@@ -1,150 +0,0 @@
-use crate::*;
-use std::time::Duration;
-use std::thread::{spawn, JoinHandle};
-use unicode_width::*;
-
-#[derive(Default)]
-pub struct TuiOut {
-    pub buffer: Buffer,
-    pub area:   [u16;4]
-}
-
-impl Out for TuiOut {
-    type Unit = u16;
-    type Size = [Self::Unit;2];
-    type Area = [Self::Unit;4];
-    #[inline] fn area (&self) -> [u16;4] {
-        self.area
-    }
-    #[inline] fn area_mut (&mut self) -> &mut [u16;4] {
-        &mut self.area
-    }
-    #[inline] fn place_at <'t, T: Draw<Self> + ?Sized> (&mut self, area: [u16;4], content: &'t T) {
-        let last = self.area();
-        *self.area_mut() = area;
-        content.draw(self);
-        *self.area_mut() = last;
-    }
-}
-
-impl TuiOut {
-    /// Spawn the output thread.
-    pub fn run_output <T: Draw<TuiOut> + Send + Sync + 'static> (
-        engine: &Arc<RwLock<Tui>>,
-        state:  &Arc<RwLock<T>>,
-        timer:  Duration
-    ) -> Result<JoinHandle<()>, std::io::Error> {
-        let exited = engine.read().unwrap().exited.clone();
-        let engine = engine.clone();
-        let state  = state.clone();
-        let Size { width, height } = engine.read().unwrap().backend.size().expect("get size failed");
-        let mut buffer = Buffer::empty(Rect { x: 0, y: 0, width, height });
-        std::thread::Builder::new()
-            .name("tui output thread".into())
-            .spawn(move || loop {
-                if exited.fetch_and(true, Relaxed) {
-                    break
-                }
-                let t0 = engine.read().unwrap().perf.get_t0();
-                let Size { width, height } = engine.read().unwrap().backend.size()
-                    .expect("get size failed");
-                if let Ok(state) = state.try_read() {
-                    let size = Rect { x: 0, y: 0, width, height };
-                    if buffer.area != size {
-                        engine.write().unwrap().backend.clear_region(ClearType::All).expect("clear failed");
-                        buffer.resize(size);
-                        buffer.reset();
-                    }
-                    let mut output = TuiOut { buffer, area: [0, 0, width, height] };
-                    state.draw(&mut output);
-                    buffer = engine.write().unwrap().flip(output.buffer, size);
-                }
-                let t1 = engine.read().unwrap().perf.get_t1(t0).unwrap();
-                buffer.set_string(0, 0, &format!("{:>3}.{:>3}ms", t1.as_millis(), t1.as_micros() % 1000), Style::default());
-                std::thread::sleep(timer);
-            })
-    }
-    #[inline]
-    pub fn with_rect (&mut self, area: [u16;4]) -> &mut Self {
-        self.area = area;
-        self
-    }
-    pub fn blit (
-        &mut self, text: &impl AsRef<str>, x: u16, y: u16, style: Option<Style>
-    ) {
-        let text  = text.as_ref();
-        let buf   = &mut self.buffer;
-        let style = style.unwrap_or(Style::default());
-        if x < buf.area.width && y < buf.area.height {
-            buf.set_string(x, y, text, style);
-        }
-    }
-    /// Write a line of text
-    ///
-    /// TODO: do a paragraph (handle newlines)
-    pub fn text (&mut self, text: &impl AsRef<str>, x0: u16, y: u16, max_width: u16) {
-        let text = text.as_ref();
-        let buf  = &mut self.buffer;
-        let mut string_width: u16 = 0;
-        for character in text.chars() {
-            let x = x0 + string_width;
-            let character_width = character.width().unwrap_or(0) as u16;
-            string_width += character_width;
-            if string_width > max_width {
-                break
-            }
-            if let Some(cell) = buf.cell_mut(ratatui::prelude::Position { x, y }) {
-                cell.set_char(character);
-            } else {
-                break
-            }
-        }
-    }
-    pub fn buffer_update (&mut self, area: [u16;4], callback: &impl Fn(&mut Cell, u16, u16)) {
-        buffer_update(&mut self.buffer, area, callback);
-    }
-    pub fn fill_char (&mut self, area: [u16;4], c: char) {
-        self.buffer_update(area, &|cell,_,_|{cell.set_char(c);})
-    }
-    pub fn fill_bg (&mut self, area: [u16;4], color: Color) {
-        self.buffer_update(area, &|cell,_,_|{cell.set_bg(color);})
-    }
-    pub fn fill_fg (&mut self, area: [u16;4], color: Color) {
-        self.buffer_update(area, &|cell,_,_|{cell.set_fg(color);})
-    }
-    pub fn fill_mod (&mut self, area: [u16;4], on: bool, modifier: Modifier) {
-        if on {
-            self.buffer_update(area, &|cell,_,_|cell.modifier.insert(modifier))
-        } else {
-            self.buffer_update(area, &|cell,_,_|cell.modifier.remove(modifier))
-        }
-    }
-    pub fn fill_bold (&mut self, area: [u16;4], on: bool) {
-        self.fill_mod(area, on, Modifier::BOLD)
-    }
-    pub fn fill_reversed (&mut self, area: [u16;4], on: bool) {
-        self.fill_mod(area, on, Modifier::REVERSED)
-    }
-    pub fn fill_crossed_out (&mut self, area: [u16;4], on: bool) {
-        self.fill_mod(area, on, Modifier::CROSSED_OUT)
-    }
-    pub fn fill_ul (&mut self, area: [u16;4], color: Option<Color>) {
-        if let Some(color) = color {
-            self.buffer_update(area, &|cell,_,_|{
-                cell.modifier.insert(ratatui::prelude::Modifier::UNDERLINED);
-                cell.underline_color = color;
-            })
-        } else {
-            self.buffer_update(area, &|cell,_,_|{
-                cell.modifier.remove(ratatui::prelude::Modifier::UNDERLINED);
-            })
-        }
-    }
-    pub fn tint_all (&mut self, fg: Color, bg: Color, modifier: Modifier) {
-        for cell in self.buffer.content.iter_mut() {
-            cell.fg = fg;
-            cell.bg = bg;
-            cell.modifier = modifier;
-        }
-    }
-}
diff --git a/tui/src/tui_engine/tui_perf.rs b/tui/src/tui_engine/tui_perf.rs
deleted file mode 100644
index 21fc338..0000000
--- a/tui/src/tui_engine/tui_perf.rs
+++ /dev/null
@@ -1,64 +0,0 @@
-use crate::*;
-
-/// Performance counter
-#[derive(Debug)]
-pub struct PerfModel {
-    pub enabled: bool,
-    pub clock:  quanta::Clock,
-    // In nanoseconds. Time used by last iteration.
-    pub used:   AtomicF64,
-    // In microseconds. Max prescribed time for iteration (frame, chunk...). 
-    pub window: AtomicF64,
-}
-
-pub trait HasPerf {
-    fn perf (&self) -> &PerfModel;
-}
-
-impl Default for PerfModel {
-    fn default () -> Self {
-        Self {
-            enabled: true,
-            clock:   quanta::Clock::new(),
-            used:    Default::default(),
-            window:  Default::default(),
-        }
-    }
-}
-
-impl PerfModel {
-    pub fn get_t0 (&self) -> Option<u64> {
-        if self.enabled {
-            Some(self.clock.raw())
-        } else {
-            None
-        }
-    }
-    pub fn get_t1 (&self, t0: Option<u64>) -> Option<std::time::Duration> {
-        if let Some(t0) = t0 {
-            if self.enabled {
-                Some(self.clock.delta(t0, self.clock.raw()))
-            } else {
-                None
-            }
-        } else {
-            None
-        }
-    }
-    pub fn update (&self, t0: Option<u64>, microseconds: f64) {
-        if let Some(t0) = t0 {
-            let t1 = self.clock.raw();
-            self.used.store(self.clock.delta_as_nanos(t0, t1) as f64, Relaxed);
-            self.window.store(microseconds, Relaxed,);
-        }
-    }
-    pub fn percentage (&self) -> Option<f64> {
-        let window = self.window.load(Relaxed) * 1000.0;
-        if window > 0.0 {
-            let used = self.used.load(Relaxed);
-            Some(100.0 * used / window)
-        } else {
-            None
-        }
-    }
-}
diff --git a/tui/src/tui_impls.rs b/tui/src/tui_impls.rs
new file mode 100644
index 0000000..a87df69
--- /dev/null
+++ b/tui/src/tui_impls.rs
@@ -0,0 +1,885 @@
+use crate::*;
+use ratatui::style::Stylize;
+use ratatui::{prelude::Position, style::Color::*};
+use crate::ratatui::prelude::Position;
+use unicode_width::{UnicodeWidthStr, UnicodeWidthChar};
+use ratatui::prelude::Position;
+use rand::{thread_rng, distributions::uniform::UniformSampler};
+
+impl Tui {
+    pub const fn fg     <T>    (color: Color, w: T) -> Foreground<Color, T> { Foreground(color, w) }
+    pub const fn bg     <T>    (color: Color, w: T) -> Background<Color, T> { Background(color, w) }
+    pub const fn fg_bg  <T>    (fg: Color, bg: Color, w: T) -> Background<Color, Foreground<Color, T>> { Background(bg, Foreground(fg, w)) }
+    pub const fn modify <T>    (enable: bool, modifier: Modifier, w: T) -> Modify<T> { Modify(enable, modifier, w) }
+    pub const fn bold   <T>    (enable: bool, w: T) -> Modify<T> { Self::modify(enable, Modifier::BOLD, w) }
+    pub const fn border <S, T> (enable: bool, style: S, w: T) -> Bordered<S, T> { Bordered(enable, style, w) }
+    pub const fn null     () -> Color { Color::Reset }
+    pub const fn g   (g: u8) -> Color { Color::Rgb(g, g, g) }
+    pub const fn red      () -> Color { Color::Rgb(255,0,  0) }
+    pub const fn orange   () -> Color { Color::Rgb(255,128,0) }
+    pub const fn yellow   () -> Color { Color::Rgb(255,255,0) }
+    pub const fn brown    () -> Color { Color::Rgb(128,255,0) }
+    pub const fn green    () -> Color { Color::Rgb(0,255,0) }
+    pub const fn electric () -> Color { Color::Rgb(0,255,128) }
+    //fn bg0  () -> Color { Color::Rgb(20, 20, 20) }
+    //fn bg   () -> Color { Color::Rgb(28, 35, 25) }
+    //fn border_bg () -> Color { Color::Rgb(40, 50, 30) }
+    //fn border_fg (f: bool) -> Color { if f { Self::bo1() } else { Self::bo2() } }
+    //fn title_fg (f: bool) -> Color { if f { Self::ti1() } else { Self::ti2() } }
+    //fn separator_fg (_: bool) -> Color { Color::Rgb(0, 0, 0) }
+    //fn mode_bg () -> Color { Color::Rgb(150, 160, 90) }
+    //fn mode_fg () -> Color { Color::Rgb(255, 255, 255) }
+    //fn status_bar_bg () -> Color { Color::Rgb(28, 35, 25) }
+    //fn bo1 () -> Color { Color::Rgb(100, 110, 40) }
+    //fn bo2 () -> Color { Color::Rgb(70, 80, 50) }
+    //fn ti1 () -> Color { Color::Rgb(150, 160, 90) }
+    //fn ti2 () -> Color { Color::Rgb(120, 130, 100) }
+    /// Construct a new TUI engine and wrap it for shared ownership.
+    pub fn new () -> Usually<Arc<RwLock<Self>>> {
+        let backend = CrosstermBackend::new(stdout());
+        let Size { width, height } = backend.size()?;
+        Ok(Arc::new(RwLock::new(Self {
+            exited:  Arc::new(AtomicBool::new(false)),
+            buffer:  Buffer::empty(Rect { x: 0, y: 0, width, height }),
+            area:    [0, 0, width, height],
+            backend,
+            perf: Default::default(),
+        })))
+    }
+    /// True if done
+    pub fn exited (&self) -> bool {
+        self.exited.fetch_and(true, Relaxed)
+    }
+    /// Prepare before run
+    pub fn setup (&mut self) -> Usually<()> {
+        let better_panic_handler = Settings::auto().verbosity(Verbosity::Full).create_panic_handler();
+        std::panic::set_hook(Box::new(move |info: &std::panic::PanicHookInfo|{
+            stdout().execute(LeaveAlternateScreen).unwrap();
+            CrosstermBackend::new(stdout()).show_cursor().unwrap();
+            disable_raw_mode().unwrap();
+            better_panic_handler(info);
+        }));
+        stdout().execute(EnterAlternateScreen)?;
+        self.backend.hide_cursor()?;
+        enable_raw_mode().map_err(Into::into)
+    }
+    /// Update the display buffer.
+    pub fn flip (&mut self, mut buffer: Buffer, size: ratatui::prelude::Rect) -> Buffer {
+        if self.buffer.area != size {
+            self.backend.clear_region(ClearType::All).unwrap();
+            self.buffer.resize(size);
+            self.buffer.reset();
+        }
+        let updates = self.buffer.diff(&buffer);
+        self.backend.draw(updates.into_iter()).expect("failed to render");
+        self.backend.flush().expect("failed to flush output buffer");
+        std::mem::swap(&mut self.buffer, &mut buffer);
+        buffer.reset();
+        buffer
+    }
+    /// Clean up after run
+    pub fn teardown (&mut self) -> Usually<()> {
+        stdout().execute(LeaveAlternateScreen)?;
+        self.backend.show_cursor()?;
+        disable_raw_mode().map_err(Into::into)
+    }
+}
+
+impl<T: TuiWidget + Send + Sync + 'static> TuiRun<T> for Arc<RwLock<Tui>> {
+    fn run (&self, state: &Arc<RwLock<T>>) -> Usually<()> {
+        let _input_thread = TuiIn::run_input(self, state, Duration::from_millis(100));
+        self.write().unwrap().setup()?;
+        let render_thread = TuiOut::run_output(self, state, Duration::from_millis(10))?;
+        match render_thread.join() {
+            Ok(result) => {
+                self.write().unwrap().teardown()?;
+                println!("\n\rRan successfully: {result:?}\n\r");
+            },
+            Err(error) => {
+                self.write().unwrap().teardown()?;
+                panic!("\n\rDraw thread failed: error={error:?}.\n\r")
+            },
+        }
+        Ok(())
+    }
+}
+
+impl Ord for TuiEvent {
+    fn cmp (&self, other: &Self) -> std::cmp::Ordering {
+        self.partial_cmp(other)
+            .unwrap_or_else(||format!("{:?}", self).cmp(&format!("{other:?}"))) // FIXME perf
+    }
+}
+
+impl TuiEvent {
+    pub fn from_crossterm (event: Event) -> Self {
+        Self(event)
+    }
+    #[cfg(feature = "dsl")]
+    pub fn from_dsl (dsl: impl Language) -> Perhaps<Self> {
+        Ok(TuiKey::from_dsl(dsl)?.to_crossterm().map(Self))
+    }
+}
+
+impl TuiKey {
+    const SPLIT: char = '/';
+    #[cfg(feature = "dsl")]
+    pub fn from_dsl (dsl: impl Language) -> Usually<Self> {
+        if let Some(word) = dsl.word()? {
+            let word = word.trim();
+            Ok(if word == ":char" {
+                Self(None, KeyModifiers::NONE)
+            } else if word.chars().nth(0) == Some('@') {
+                let mut key       = None;
+                let mut modifiers = KeyModifiers::NONE;
+                let mut tokens    = word[1..].split(Self::SPLIT).peekable();
+                while let Some(token) = tokens.next() {
+                    if tokens.peek().is_some() {
+                        match token {
+                            "ctrl"  | "Ctrl"  | "c" | "C" => modifiers |= KeyModifiers::CONTROL,
+                            "alt"   | "Alt"   | "m" | "M" => modifiers |= KeyModifiers::ALT,
+                            "shift" | "Shift" | "s" | "S" => {
+                                modifiers |= KeyModifiers::SHIFT;
+                                // + TODO normalize character case, BackTab, etc.
+                            },
+                            _ => panic!("unknown modifier {token}"),
+                        }
+                    } else {
+                        key = if token.len() == 1 {
+                            Some(KeyCode::Char(token.chars().next().unwrap()))
+                        } else {
+                            Some(named_key(token).unwrap_or_else(||panic!("unknown character {token}")))
+                        }
+                    }
+                }
+                Self(key, modifiers)
+            } else {
+                return Err(format!("TuiKey: unexpected: {word}").into())
+            })
+        } else {
+            return Err(format!("TuiKey: unspecified").into())
+        }
+    }
+    pub fn to_crossterm (&self) -> Option<Event> {
+        self.0.map(|code|Event::Key(KeyEvent {
+            code,
+            modifiers: self.1,
+            kind:  KeyEventKind::Press,
+            state: KeyEventState::NONE,
+        }))
+    }
+}
+
+pub fn buffer_update (buf: &mut Buffer, area: XY<u16>, callback: &impl Fn(&mut Cell, u16, u16)) {
+    for row in 0..area.h() {
+        let y = area.y() + row;
+        for col in 0..area.w() {
+            let x = area.x() + col;
+            if x < buf.area.width && y < buf.area.height {
+                if let Some(cell) = buf.cell_mut(ratatui::prelude::Position { x, y }) {
+                    callback(cell, col, row);
+                }
+            }
+        }
+    }
+}
+
+impl_debug!(BigBuffer |self, f| {
+    write!(f, "[BB {}x{} ({})]", self.width, self.height, self.content.len())
+});
+
+impl BigBuffer {
+    pub fn new (width: usize, height: usize) -> Self {
+        Self { width, height, content: vec![Cell::default(); width*height] }
+    }
+    pub fn get (&self, x: usize, y: usize) -> Option<&Cell> {
+        let i = self.index_of(x, y);
+        self.content.get(i)
+    }
+    pub fn get_mut (&mut self, x: usize, y: usize) -> Option<&mut Cell> {
+        let i = self.index_of(x, y);
+        self.content.get_mut(i)
+    }
+    pub fn index_of (&self, x: usize, y: usize) -> usize {
+        y * self.width + x
+    }
+}
+
+from!(BigBuffer: |size:(usize, usize)| Self::new(size.0, size.1));
+impl Input for TuiIn {
+    type Event   = TuiEvent;
+    type Handled = bool;
+    fn event   (&self) -> &TuiEvent { &self.event }
+    fn is_done (&self) -> bool { self.exited.fetch_and(true, Relaxed) }
+    fn done    (&self) { self.exited.store(true, Relaxed); }
+}
+impl TuiIn {
+    /// Spawn the input thread.
+    pub fn run_input <T: Handle<TuiIn> + Send + Sync + 'static> (
+        engine: &Arc<RwLock<Tui>>,
+        state:  &Arc<RwLock<T>>,
+        timer:  Duration
+    ) -> JoinHandle<()> {
+        let exited = engine.read().unwrap().exited.clone();
+        let state  = state.clone();
+        spawn(move || loop {
+            if exited.fetch_and(true, Relaxed) {
+                break
+            }
+            if poll(timer).is_ok() {
+                let event = read().unwrap();
+                match event {
+                    Event::Key(KeyEvent {
+                        code:      KeyCode::Char('c'),
+                        modifiers: KeyModifiers::CONTROL,
+                        kind:      KeyEventKind::Press,
+                        state:     KeyEventState::NONE
+                    }) => {
+                        exited.store(true, Relaxed);
+                    },
+                    _ => {
+                        let exited = exited.clone();
+                        let event  = TuiEvent::from_crossterm(event);
+                        if let Err(e) = state.write().unwrap().handle(&TuiIn { exited, event }) {
+                            panic!("{e}")
+                        }
+                    }
+                }
+            }
+        })
+    }
+}
+
+pub trait HasPerf {
+    fn perf (&self) -> &PerfModel;
+}
+
+impl Default for PerfModel {
+    fn default () -> Self {
+        Self {
+            enabled: true,
+            clock:   quanta::Clock::new(),
+            used:    Default::default(),
+            window:  Default::default(),
+        }
+    }
+}
+
+impl PerfModel {
+    pub fn get_t0 (&self) -> Option<u64> {
+        if self.enabled {
+            Some(self.clock.raw())
+        } else {
+            None
+        }
+    }
+    pub fn get_t1 (&self, t0: Option<u64>) -> Option<std::time::Duration> {
+        if let Some(t0) = t0 {
+            if self.enabled {
+                Some(self.clock.delta(t0, self.clock.raw()))
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+    pub fn update (&self, t0: Option<u64>, microseconds: f64) {
+        if let Some(t0) = t0 {
+            let t1 = self.clock.raw();
+            self.used.store(self.clock.delta_as_nanos(t0, t1) as f64, Relaxed);
+            self.window.store(microseconds, Relaxed,);
+        }
+    }
+    pub fn percentage (&self) -> Option<f64> {
+        let window = self.window.load(Relaxed) * 1000.0;
+        if window > 0.0 {
+            let used = self.used.load(Relaxed);
+            Some(100.0 * used / window)
+        } else {
+            None
+        }
+    }
+}
+
+from!(ItemColor: |okhsl: Okhsl<f32>|Self { okhsl, rgb: okhsl_to_rgb(okhsl) });
+from!(ItemColor: |rgb: Color|Self { rgb, okhsl: rgb_to_okhsl(rgb) });
+pub fn okhsl_to_rgb (color: Okhsl<f32>) -> Color {
+    let Srgb { red, green, blue, .. }: Srgb<f32> = Srgb::from_color_unclamped(color);
+    Color::Rgb((red   * 255.0) as u8, (green * 255.0) as u8, (blue  * 255.0) as u8,)
+}
+pub fn rgb_to_okhsl (color: Color) -> Okhsl<f32> {
+    if let Color::Rgb(r, g, b) = color {
+        Okhsl::from_color(Srgb::new(r as f32 / 255.0, g as f32 / 255.0, b as f32 / 255.0))
+    } else {
+        unreachable!("only Color::Rgb is supported")
+    }
+}
+
+// A single color within item theme parameters, in OKHSL and RGB representations.
+impl ItemColor {
+    pub const fn from_rgb (rgb: Color) -> Self {
+        Self { rgb, okhsl: Okhsl::new_const(OklabHue::new(0.0), 0.0, 0.0) }
+    }
+    pub const fn from_okhsl (okhsl: Okhsl<f32>) -> Self {
+        Self { rgb: Color::Rgb(0, 0, 0), okhsl }
+    }
+    pub fn random () -> Self {
+        let mut rng = thread_rng();
+        let lo = Okhsl::new(-180.0, 0.01, 0.25);
+        let hi = Okhsl::new( 180.0, 0.9,  0.5);
+        UniformOkhsl::new(lo, hi).sample(&mut rng).into()
+    }
+    pub fn random_dark () -> Self {
+        let mut rng = thread_rng();
+        let lo = Okhsl::new(-180.0, 0.025, 0.075);
+        let hi = Okhsl::new( 180.0, 0.5,   0.150);
+        UniformOkhsl::new(lo, hi).sample(&mut rng).into()
+    }
+    pub fn random_near (color: Self, distance: f32) -> Self {
+        color.mix(Self::random(), distance)
+    }
+    pub fn mix (&self, other: Self, distance: f32) -> Self {
+        if distance > 1.0 { panic!("color mixing takes distance between 0.0 and 1.0"); }
+        self.okhsl.mix(other.okhsl, distance).into()
+    }
+}
+
+
+from!(ItemTheme: |base: Color|    Self::from_tui_color(base));
+from!(ItemTheme: |base: ItemColor|Self::from_item_color(base));
+impl ItemTheme {
+    pub const G: [Self;256] = {
+        let mut builder = konst::array::ArrayBuilder::new();
+        while !builder.is_full() {
+            let index    = builder.len() as u8;
+            let light    = (index as f64 * 1.15) as u8;
+            let lighter  = (index as f64 * 1.7) as u8;
+            let lightest = (index as f64 * 1.85) as u8;
+            let dark     = (index as f64 * 0.9) as u8;
+            let darker   = (index as f64 * 0.6) as u8;
+            let darkest  = (index as f64 * 0.3) as u8;
+            builder.push(ItemTheme {
+                base:     ItemColor::from_rgb(Color::Rgb(index,    index,    index     )),
+                light:    ItemColor::from_rgb(Color::Rgb(light,    light,    light,    )),
+                lighter:  ItemColor::from_rgb(Color::Rgb(lighter,  lighter,  lighter,  )),
+                lightest: ItemColor::from_rgb(Color::Rgb(lightest, lightest, lightest, )),
+                dark:     ItemColor::from_rgb(Color::Rgb(dark,     dark,     dark,     )),
+                darker:   ItemColor::from_rgb(Color::Rgb(darker,   darker,   darker,   )),
+                darkest:  ItemColor::from_rgb(Color::Rgb(darkest,  darkest,  darkest,  )),
+            });
+        }
+        builder.build()
+    };
+    pub fn random () -> Self { ItemColor::random().into() }
+    pub fn random_near (color: Self, distance: f32) -> Self {
+        color.base.mix(ItemColor::random(), distance).into()
+    }
+    pub const G00: Self = {
+        let color: ItemColor = ItemColor {
+            okhsl: Okhsl { hue: OklabHue::new(0.0), lightness: 0.0, saturation: 0.0 },
+            rgb: Color::Rgb(0, 0, 0)
+        };
+        Self {
+            base:     color,
+            light:    color,
+            lighter:  color,
+            lightest: color,
+            dark:     color,
+            darker:   color,
+            darkest:  color,
+        }
+    };
+    pub fn from_tui_color (base: Color) -> Self {
+        Self::from_item_color(ItemColor::from_rgb(base))
+    }
+    pub fn from_item_color (base: ItemColor) -> Self {
+        let mut light      = base.okhsl;
+        light.lightness    = (light.lightness    * 1.3).min(1.0);
+        let mut lighter    = light;
+        lighter.lightness  = (lighter.lightness  * 1.3).min(1.0);
+        let mut lightest   = base.okhsl;
+        lightest.lightness = 0.95;
+        let mut dark       = base.okhsl;
+        dark.lightness     = (dark.lightness     * 0.75).max(0.0);
+        dark.saturation    = (dark.saturation    * 0.75).max(0.0);
+        let mut darker     = dark;
+        darker.lightness   = (darker.lightness   * 0.66).max(0.0);
+        darker.saturation  = (darker.saturation  * 0.66).max(0.0);
+        let mut darkest    = darker;
+        darkest.lightness  = 0.1;
+        darkest.saturation = (darkest.saturation * 0.50).max(0.0);
+        Self {
+            base,
+            light:    light.into(),
+            lighter:  lighter.into(),
+            lightest: lightest.into(),
+            dark:     dark.into(),
+            darker:   darker.into(),
+            darkest:  darkest.into(),
+        }
+    }
+}
+
+impl Draw<TuiOut> for u64 {
+    fn draw (&self, _to: &mut TuiOut) {
+        todo!()
+    }
+}
+
+impl Draw<TuiOut> for f64 {
+    fn draw (&self, _to: &mut TuiOut) {
+        todo!()
+    }
+}
+
+impl<T> Phat<T> {
+    pub const LO: &'static str = "▄";
+    pub const HI: &'static str = "▀";
+    /// A phat line
+    pub fn lo (fg: Color, bg: Color) -> impl Content<TuiOut> { Fixed::Y(1, Tui::fg_bg(fg, bg, RepeatH(Self::LO))) }
+    /// A phat line
+    pub fn hi (fg: Color, bg: Color) -> impl Content<TuiOut> { Fixed::Y(1, Tui::fg_bg(fg, bg, RepeatH(Self::HI))) }
+}
+
+impl<T: Content<TuiOut>> HasContent<TuiOut> for Phat<T> {
+    fn content (&self) -> impl Content<TuiOut> {
+        let [fg, bg, hi, lo] = self.colors;
+        let top = Fixed::Y(1, Self::lo(bg, hi));
+        let low = Fixed::Y(1, Self::hi(bg, lo));
+        let content = Tui::fg_bg(fg, bg, &self.content);
+        Min::XY(self.width, self.height, Bsp::s(top, Bsp::n(low, Fill::XY(content))))
+    }
+}
+
+impl Draw<TuiOut> for Repeat<'_> {
+    fn draw (&self, to: &mut TuiOut) {
+        let [x, y, w, h] = to.area().xywh();
+        let a = self.0.len();
+        for (_v, y) in (y..y+h).enumerate() {
+            for (u, x) in (x..x+w).enumerate() {
+                if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
+                    let u = u % a;
+                    cell.set_symbol(&self.0[u..u+1]);
+                }
+            }
+        }
+    }
+}
+
+impl Layout<TuiOut> for RepeatV<'_> {}
+impl Draw<TuiOut> for RepeatV<'_> {
+    fn draw (&self, to: &mut TuiOut) {
+        let [x, y, _w, h] = to.area().xywh();
+        for y in y..y+h {
+            if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
+                cell.set_symbol(&self.0);
+            }
+        }
+    }
+}
+
+impl Layout<TuiOut> for RepeatH<'_> {}
+impl Draw<TuiOut> for RepeatH<'_> {
+    fn draw (&self, to: &mut TuiOut) {
+        let [x, y, w, _h] = to.area().xywh();
+        for x in x..x+w {
+            if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
+                cell.set_symbol(&self.0);
+            }
+        }
+    }
+}
+
+impl ScrollbarV {
+    const ICON_DEC: &[char] = &['▲'];
+    const ICON_INC: &[char] = &['▼'];
+}
+
+impl ScrollbarH {
+    const ICON_DEC: &[char] = &[' ', '🞀', ' '];
+    const ICON_INC: &[char] = &[' ', '🞂', ' '];
+}
+
+impl Draw<TuiOut> for ScrollbarV {
+    fn draw (&self, to: &mut TuiOut) {
+        let [x, y1, _w, h] = to.area().xywh();
+        let y2 = y1 + h;
+        for (i, y) in (y1..=y2).enumerate() {
+            if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
+                if (i as usize) < (Self::ICON_DEC.len()) {
+                    cell.set_fg(Rgb(255, 255, 255));
+                    cell.set_bg(Rgb(0, 0, 0));
+                    cell.set_char(Self::ICON_DEC[i as usize]);
+                } else if (i as usize) > (h as usize - Self::ICON_INC.len()) {
+                    cell.set_fg(Rgb(255, 255, 255));
+                    cell.set_bg(Rgb(0, 0, 0));
+                    cell.set_char(Self::ICON_INC[h as usize - i]);
+                } else if false {
+                    cell.set_fg(Rgb(255, 255, 255));
+                    cell.set_bg(Reset);
+                    cell.set_char('‖'); // ━
+                } else {
+                    cell.set_fg(Rgb(0, 0, 0));
+                    cell.set_bg(Reset);
+                    cell.set_char('╎'); // ━
+                }
+            }
+        }
+    }
+}
+
+impl Draw<TuiOut> for ScrollbarH {
+    fn draw (&self, to: &mut TuiOut) {
+        let [x1, y, w, _h] = to.area().xywh();
+        let x2 = x1 + w;
+        for (i, x) in (x1..=x2).enumerate() {
+            if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
+                if i < (Self::ICON_DEC.len()) {
+                    cell.set_fg(Rgb(255, 255, 255));
+                    cell.set_bg(Rgb(0, 0, 0));
+                    cell.set_char(Self::ICON_DEC[i as usize]);
+                } else if i > (w as usize - Self::ICON_INC.len()) {
+                    cell.set_fg(Rgb(255, 255, 255));
+                    cell.set_bg(Rgb(0, 0, 0));
+                    cell.set_char(Self::ICON_INC[w as usize - i]);
+                } else if false {
+                    cell.set_fg(Rgb(255, 255, 255));
+                    cell.set_bg(Reset);
+                    cell.set_char('━');
+                } else {
+                    cell.set_fg(Rgb(0, 0, 0));
+                    cell.set_bg(Reset);
+                    cell.set_char('╌');
+                }
+            }
+        }
+    }
+}
+
+impl Draw<TuiOut> for &str {
+    fn draw (&self, to: &mut TuiOut) {
+        let [x, y, w, ..] = self.layout(to.area());
+        to.text(&self, x, y, w)
+    }
+}
+impl Draw<TuiOut> for String {
+    fn draw (&self, to: &mut TuiOut) {
+        self.as_str().draw(to)
+    }
+}
+impl Draw<TuiOut> for Arc<str> {
+    fn draw (&self, to: &mut TuiOut) { self.as_ref().draw(to) }
+}
+
+impl Layout<TuiOut> for &str {
+    fn layout (&self, to: XY<u16>) -> XY<u16> { to.center_xy([width_chars_max(to.w(), self), 1]) }
+}
+impl Layout<TuiOut> for String {
+    fn layout (&self, to: XY<u16>) -> XY<u16> {
+        self.as_str().layout(to)
+    }
+}
+impl Layout<TuiOut> for Arc<str> {
+    fn layout (&self, to: XY<u16>) -> XY<u16> {
+        self.as_ref().layout(to)
+    }
+}
+
+fn width_chars_max (max: u16, text: impl AsRef<str>) -> u16 {
+    let mut width: u16 = 0;
+    let mut chars = text.as_ref().chars();
+    while let Some(c) = chars.next() {
+        width += c.width().unwrap_or(0) as u16;
+        if width > max {
+            break
+        }
+    }
+    return width
+}
+
+/// Trim string with [unicode_width].
+pub fn trim_string (max_width: usize, input: impl AsRef<str>) -> String {
+    let input = input.as_ref();
+    let mut output = Vec::with_capacity(input.len());
+    let mut width: usize = 1;
+    let mut chars = input.chars();
+    while let Some(c) = chars.next() {
+        if width > max_width {
+            break
+        }
+        output.push(c);
+        width += c.width().unwrap_or(0);
+    }
+    return output.into_iter().collect()
+}
+
+
+impl<'a, T: AsRef<str>> TrimString<T> {
+    fn as_ref (&self) -> TrimStringRef<'_, T> { TrimStringRef(self.0, &self.1) }
+}
+impl<'a, T: AsRef<str>> Draw<TuiOut> for TrimString<T> {
+    fn draw (&self, to: &mut TuiOut) { Draw::draw(&self.as_ref(), to) }
+}
+impl<'a, T: AsRef<str>> Layout<TuiOut> for TrimString<T> {
+    fn layout (&self, to: XY<u16>) -> XY<u16> { Layout::layout(&self.as_ref(), to) }
+}
+
+impl<'a, T: AsRef<str>> Layout<TuiOut> for TrimStringRef<'a, T> {
+    fn layout (&self, to: XY<u16>) -> XY<u16> {
+        [to.x(), to.y(), to.w().min(self.0).min(self.1.as_ref().width() as u16), to.h()]
+    }
+}
+impl<T: AsRef<str>> Draw<TuiOut> for TrimStringRef<'_, T> {
+    fn draw (&self, target: &mut TuiOut) {
+        let area = target.area();
+        let mut width: u16 = 1;
+        let mut chars = self.1.as_ref().chars();
+        while let Some(c) = chars.next() {
+            if width > self.0 || width > area.w() {
+                break
+            }
+            if let Some(cell) = target.buffer.cell_mut(Position {
+                x: area.x() + width - 1,
+                y: area.y()
+            }) {
+                cell.set_char(c);
+            }
+            width += c.width().unwrap_or(0) as u16;
+        }
+    }
+}
+
+impl<
+    A: Content<TuiOut>,
+    B: Content<TuiOut>,
+    C: Content<TuiOut>,
+> HasContent<TuiOut> for Tryptich<A, B, C> {
+    fn content (&self) -> impl Content<TuiOut> {
+        let Self { top, h, left: (w_a, ref a), middle: (w_b, ref b), right: (w_c, ref c) } = *self;
+        Fixed::Y(h, if top {
+            Bsp::a(
+                Fill::X(Align::n(Fixed::X(w_b, Align::x(Tui::bg(Color::Reset, b))))),
+                Bsp::a(
+                    Fill::X(Align::nw(Fixed::X(w_a, Tui::bg(Color::Reset, a)))),
+                    Fill::X(Align::ne(Fixed::X(w_c, Tui::bg(Color::Reset, c)))),
+                ),
+            )
+        } else {
+            Bsp::a(
+                Fill::XY(Align::c(Fixed::X(w_b, Align::x(Tui::bg(Color::Reset, b))))),
+                Bsp::a(
+                    Fill::XY(Align::w(Fixed::X(w_a, Tui::bg(Color::Reset, a)))),
+                    Fill::XY(Align::e(Fixed::X(w_c, Tui::bg(Color::Reset, c)))),
+                ),
+            )
+        })
+    }
+}
+
+impl<O: Out, T: Draw<O>> ErrorBoundary<O, T> {
+    pub fn new (content: Perhaps<T>) -> Self {
+        Self(Default::default(), content)
+    }
+}
+
+impl<T: Draw<TuiOut>> Draw<TuiOut> for ErrorBoundary<TuiOut, T> {
+    fn draw (&self, to: &mut TuiOut) {
+        match self.1.as_ref() {
+            Ok(Some(content)) => content.draw(to),
+            Ok(None) => to.blit(&"empty?", 0, 0, Some(Style::default().yellow())),
+            Err(e) => {
+                let err_fg = Color::Rgb(255,224,244);
+                let err_bg = Color::Rgb(96,24,24);
+                let title  = Bsp::e(Tui::bold(true, "oops. "), "rendering failed.");
+                let error  = Bsp::e("\"why?\" ", Tui::bold(true, format!("{e}")));
+                to.place(&Tui::fg_bg(err_fg, err_bg, Bsp::s(title, error)))
+            }
+        }
+    }
+}
+
+impl<S: BorderStyle, W: Content<TuiOut>> HasContent<TuiOut> for Bordered<S, W> {
+    fn content (&self) -> impl Content<TuiOut> {
+        Fill::XY(lay!( When::new(self.0, Border(self.0, self.1)), Pad::XY(1, 1, &self.2) ))
+    }
+}
+
+impl<S: BorderStyle> Draw<TuiOut> for Border<S> {
+    fn draw (&self, to: &mut TuiOut) {
+        let Border(enabled, style) = self;
+        if *enabled {
+            let area = to.area();
+            if area.w() > 0 && area.y() > 0 {
+                to.blit(&style.border_nw(), area.x(), area.y(), style.style());
+                to.blit(&style.border_ne(), area.x() + area.w() - 1, area.y(), style.style());
+                to.blit(&style.border_sw(), area.x(), area.y() + area.h() - 1, style.style());
+                to.blit(&style.border_se(), area.x() + area.w() - 1, area.y() + area.h() - 1, style.style());
+                for x in area.x()+1..area.x()+area.w()-1 {
+                    to.blit(&style.border_n(), x, area.y(), style.style());
+                    to.blit(&style.border_s(), x, area.y() + area.h() - 1, style.style());
+                }
+                for y in area.y()+1..area.y()+area.h()-1 {
+                    to.blit(&style.border_w(), area.x(), y, style.style());
+                    to.blit(&style.border_e(), area.x() + area.w() - 1, y, style.style());
+                }
+            }
+        }
+    }
+}
+
+impl<T: Content<TuiOut>> Draw<TuiOut> for Foreground<Color, T> {
+    fn draw (&self, to: &mut TuiOut) {
+        let area = self.layout(to.area());
+        to.fill_fg(area, self.0);
+        to.place_at(area, &self.1);
+    }
+}
+
+impl<T: Content<TuiOut>> Draw<TuiOut> for Background<Color, T> {
+    fn draw (&self, to: &mut TuiOut) {
+        let area = self.layout(to.area());
+        to.fill_bg(area, self.0);
+        to.place_at(area, &self.1);
+    }
+}
+
+impl<T: Content<TuiOut>> Layout<TuiOut> for Modify<T> {}
+
+impl<T: Content<TuiOut>> Draw<TuiOut> for Modify<T> {
+    fn draw (&self, to: &mut TuiOut) {
+        to.fill_mod(to.area(), self.0, self.1);
+        self.2.draw(to)
+    }
+}
+
+impl<T: Content<TuiOut>> Layout<TuiOut> for Styled<T> {}
+
+impl<T: Content<TuiOut>> Draw<TuiOut> for Styled<T> {
+    fn draw (&self, to: &mut TuiOut) {
+        to.place(&self.1);
+        // TODO write style over area
+    }
+}
+
+impl TuiOut {
+    /// Spawn the output thread.
+    pub fn run_output <T: Draw<TuiOut> + Send + Sync + 'static> (
+        engine: &Arc<RwLock<Tui>>,
+        state:  &Arc<RwLock<T>>,
+        timer:  Duration
+    ) -> Result<JoinHandle<()>, std::io::Error> {
+        let exited = engine.read().unwrap().exited.clone();
+        let engine = engine.clone();
+        let state  = state.clone();
+        let Size { width, height } = engine.read().unwrap().backend.size().expect("get size failed");
+        let mut buffer = Buffer::empty(Rect { x: 0, y: 0, width, height });
+        std::thread::Builder::new()
+            .name("tui output thread".into())
+            .spawn(move || loop {
+                if exited.fetch_and(true, Relaxed) {
+                    break
+                }
+                let t0 = engine.read().unwrap().perf.get_t0();
+                let Size { width, height } = engine.read().unwrap().backend.size()
+                    .expect("get size failed");
+                if let Ok(state) = state.try_read() {
+                    let size = Rect { x: 0, y: 0, width, height };
+                    if buffer.area != size {
+                        engine.write().unwrap().backend.clear_region(ClearType::All).expect("clear failed");
+                        buffer.resize(size);
+                        buffer.reset();
+                    }
+                    let mut output = TuiOut { buffer, area: [0, 0, width, height] };
+                    state.draw(&mut output);
+                    buffer = engine.write().unwrap().flip(output.buffer, size);
+                }
+                let t1 = engine.read().unwrap().perf.get_t1(t0).unwrap();
+                buffer.set_string(0, 0, &format!("{:>3}.{:>3}ms", t1.as_millis(), t1.as_micros() % 1000), Style::default());
+                std::thread::sleep(timer);
+            })
+    }
+    #[inline]
+    pub fn with_rect (&mut self, area: XY<u16>) -> &mut Self {
+        self.area = area;
+        self
+    }
+    pub fn blit (
+        &mut self, text: &impl AsRef<str>, x: u16, y: u16, style: Option<Style>
+    ) {
+        let text  = text.as_ref();
+        let buf   = &mut self.buffer;
+        let style = style.unwrap_or(Style::default());
+        if x < buf.area.width && y < buf.area.height {
+            buf.set_string(x, y, text, style);
+        }
+    }
+    /// Write a line of text
+    ///
+    /// TODO: do a paragraph (handle newlines)
+    pub fn text (&mut self, text: &impl AsRef<str>, x0: u16, y: u16, max_width: u16) {
+        let text = text.as_ref();
+        let buf  = &mut self.buffer;
+        let mut string_width: u16 = 0;
+        for character in text.chars() {
+            let x = x0 + string_width;
+            let character_width = character.width().unwrap_or(0) as u16;
+            string_width += character_width;
+            if string_width > max_width {
+                break
+            }
+            if let Some(cell) = buf.cell_mut(ratatui::prelude::Position { x, y }) {
+                cell.set_char(character);
+            } else {
+                break
+            }
+        }
+    }
+    pub fn buffer_update (&mut self, area: XY<u16>, callback: &impl Fn(&mut Cell, u16, u16)) {
+        buffer_update(&mut self.buffer, area, callback);
+    }
+    pub fn fill_char (&mut self, area: XY<u16>, c: char) {
+        self.buffer_update(area, &|cell,_,_|{cell.set_char(c);})
+    }
+    pub fn fill_bg (&mut self, area: XY<u16>, color: Color) {
+        self.buffer_update(area, &|cell,_,_|{cell.set_bg(color);})
+    }
+    pub fn fill_fg (&mut self, area: XY<u16>, color: Color) {
+        self.buffer_update(area, &|cell,_,_|{cell.set_fg(color);})
+    }
+    pub fn fill_mod (&mut self, area: XY<u16>, on: bool, modifier: Modifier) {
+        if on {
+            self.buffer_update(area, &|cell,_,_|cell.modifier.insert(modifier))
+        } else {
+            self.buffer_update(area, &|cell,_,_|cell.modifier.remove(modifier))
+        }
+    }
+    pub fn fill_bold (&mut self, area: XY<u16>, on: bool) {
+        self.fill_mod(area, on, Modifier::BOLD)
+    }
+    pub fn fill_reversed (&mut self, area: XY<u16>, on: bool) {
+        self.fill_mod(area, on, Modifier::REVERSED)
+    }
+    pub fn fill_crossed_out (&mut self, area: XY<u16>, on: bool) {
+        self.fill_mod(area, on, Modifier::CROSSED_OUT)
+    }
+    pub fn fill_ul (&mut self, area: XY<u16>, color: Option<Color>) {
+        if let Some(color) = color {
+            self.buffer_update(area, &|cell,_,_|{
+                cell.modifier.insert(ratatui::prelude::Modifier::UNDERLINED);
+                cell.underline_color = color;
+            })
+        } else {
+            self.buffer_update(area, &|cell,_,_|{
+                cell.modifier.remove(ratatui::prelude::Modifier::UNDERLINED);
+            })
+        }
+    }
+    pub fn tint_all (&mut self, fg: Color, bg: Color, modifier: Modifier) {
+        for cell in self.buffer.content.iter_mut() {
+            cell.fg = fg;
+            cell.bg = bg;
+            cell.modifier = modifier;
+        }
+    }
+}
diff --git a/tui/src/tui_structs.rs b/tui/src/tui_structs.rs
new file mode 100644
index 0000000..9db1c9a
--- /dev/null
+++ b/tui/src/tui_structs.rs
@@ -0,0 +1,124 @@
+use crate::*;
+
+/// The `Tui` struct (the *engine*) implements the
+/// `tengri_input::Input` and `tengri_output::Out` traits.
+/// At launch, the `Tui` engine spawns two threads, the render thread and the input thread.
+/// the application may further spawn other threads. All threads communicate using shared ownership:
+/// `Arc<RwLock<T>>` and `Arc<AtomicT>`. Thus, at launch the engine and application instances are expected to be wrapped in `Arc<RwLock>`.
+pub struct Tui {
+    pub exited:  Arc<AtomicBool>,
+    pub backend: CrosstermBackend<Stdout>,
+    pub buffer:  Buffer,
+    pub area:    [u16;4],
+    pub perf:    PerfModel,
+}
+
+#[derive(Default)] pub struct BigBuffer {
+    pub width:   usize,
+    pub height:  usize,
+    pub content: Vec<Cell>
+}
+
+#[derive(Debug, Clone, Eq, PartialEq, PartialOrd)] pub struct TuiEvent(pub Event);
+
+pub struct TuiKey(Option<KeyCode>, KeyModifiers);
+
+#[derive(Debug, Clone)]
+pub struct TuiIn {
+    /// Exit flag
+    pub exited: Arc<AtomicBool>,
+    /// Input event
+    pub event: TuiEvent,
+}
+
+/// Performance counter
+#[derive(Debug)]
+pub struct PerfModel {
+    pub enabled: bool,
+    pub clock:  quanta::Clock,
+    // In nanoseconds. Time used by last iteration.
+    pub used:   AtomicF64,
+    // In microseconds. Max prescribed time for iteration (frame, chunk...). 
+    pub window: AtomicF64,
+}
+/// A color in OKHSL and RGB representations.
+#[derive(Debug, Default, Copy, Clone, PartialEq)] pub struct ItemColor {
+    pub okhsl: Okhsl<f32>,
+    pub rgb:   Color,
+}
+/// A color in OKHSL and RGB with lighter and darker variants.
+#[derive(Debug, Default, Copy, Clone, PartialEq)] pub struct ItemTheme {
+    pub base:     ItemColor,
+    pub light:    ItemColor,
+    pub lighter:  ItemColor,
+    pub lightest: ItemColor,
+    pub dark:     ItemColor,
+    pub darker:   ItemColor,
+    pub darkest:  ItemColor,
+}
+
+/// A cell that takes up 3 rows on its own,
+/// but stacks, giving (N+1)*2 rows per N cells.
+pub struct Phat<T> {
+    pub width:   u16,
+    pub height:  u16,
+    pub content: T,
+    pub colors:  [Color;4],
+}
+pub struct Repeat<'a>(pub &'a str);
+pub struct RepeatV<'a>(pub &'a str);
+pub struct RepeatH<'a>(pub &'a str);
+
+pub struct ScrollbarV {
+    pub offset: usize,
+    pub length: usize,
+    pub total:  usize,
+}
+
+pub struct ScrollbarH {
+    pub offset: usize,
+    pub length: usize,
+    pub total:  usize,
+}
+/// Displays an owned [str]-like with fixed maximum width.
+///
+/// Width is computed using [unicode_width].
+pub struct TrimString<T: AsRef<str>>(pub u16, pub T);
+
+/// Displays a borrowed [str]-like with fixed maximum width
+///
+/// Width is computed using [unicode_width].
+pub struct TrimStringRef<'a, T: AsRef<str>>(pub u16, pub &'a T);
+
+// Thunks can be natural error boundaries!
+pub struct ErrorBoundary<O: Out, T: Draw<O>>(
+    std::marker::PhantomData<O>, Perhaps<T>
+);
+
+pub struct Modify<T>(pub bool, pub Modifier, pub T);
+
+pub struct Styled<T>(pub Option<Style>, pub T);
+
+#[derive(Default)]
+pub struct TuiOut {
+    pub buffer: Buffer,
+    pub area:   XYWH<u16>,
+}
+
+impl Out for TuiOut {
+    type Unit = u16;
+    #[inline] fn area (&self) -> XYWH<u16> {
+        self.area
+    }
+    #[inline] fn area_mut (&mut self) -> &mut XYWH<u16> {
+        &mut self.area
+    }
+    #[inline] fn place_at <'t, T: Draw<Self> + ?Sized> (
+        &mut self, area: XYWH<u16>, content: &'t T
+    ) {
+        let last = self.area();
+        *self.area_mut() = area;
+        content.draw(self);
+        *self.area_mut() = last;
+    }
+}
diff --git a/tui/src/tui_traits.rs b/tui/src/tui_traits.rs
new file mode 100644
index 0000000..8506dad
--- /dev/null
+++ b/tui/src/tui_traits.rs
@@ -0,0 +1,112 @@
+use crate::*;
+
+pub trait TuiDraw    = Draw<TuiOut>;
+
+pub trait TuiLayout  = Layout<TuiOut>;
+
+pub trait TuiContent = Content<TuiOut>;
+
+pub trait TuiHandle  = Handle<TuiIn>;
+
+pub trait TuiWidget  = TuiDraw + TuiHandle;
+
+pub trait TuiRun<T: TuiWidget + 'static> {
+    /// Run an app in the main loop.
+    fn run (&self, state: &Arc<RwLock<T>>) -> Usually<()>;
+}
+
+pub trait HasColor { fn color (&self) -> ItemColor; }
+
+pub trait BorderStyle: Content<TuiOut> + Copy {
+    fn enabled (&self) -> bool;
+    fn enclose (self, w: impl Content<TuiOut>) -> impl Content<TuiOut> {
+        Bsp::b(Fill::XY(Border(self.enabled(), self)), w)
+    }
+    fn enclose2 (self, w: impl Content<TuiOut>) -> impl Content<TuiOut> {
+        Bsp::b(Pad::XY(1, 1, Fill::XY(Border(self.enabled(), self))), w)
+    }
+    fn enclose_bg (self, w: impl Content<TuiOut>) -> impl Content<TuiOut> {
+        Tui::bg(self.style().unwrap().bg.unwrap_or(Color::Reset),
+            Bsp::b(Fill::XY(Border(self.enabled(), self)), w))
+    }
+    const NW: &'static str = "";
+    const N:  &'static str = "";
+    const NE: &'static str = "";
+    const E:  &'static str = "";
+    const SE: &'static str = "";
+    const S:  &'static str = "";
+    const SW: &'static str = "";
+    const W:  &'static str = "";
+
+    const N0: &'static str = "";
+    const S0: &'static str = "";
+    const W0: &'static str = "";
+    const E0: &'static str = "";
+
+    fn border_n (&self) -> &str { Self::N }
+    fn border_s (&self) -> &str { Self::S }
+    fn border_e (&self) -> &str { Self::E }
+    fn border_w (&self) -> &str { Self::W }
+    fn border_nw (&self) -> &str { Self::NW }
+    fn border_ne (&self) -> &str { Self::NE }
+    fn border_sw (&self) -> &str { Self::SW }
+    fn border_se (&self) -> &str { Self::SE }
+    #[inline] fn draw <'a> (
+        &self, to: &mut TuiOut
+    ) -> Usually<()> {
+        if self.enabled() {
+            self.draw_horizontal(to, None)?;
+            self.draw_vertical(to, None)?;
+            self.draw_corners(to, None)?;
+        }
+        Ok(())
+    }
+    #[inline] fn draw_horizontal (
+        &self, to: &mut TuiOut, style: Option<Style>
+    ) -> Usually<[u16;4]> {
+        let area = to.area();
+        let style = style.or_else(||self.style_horizontal());
+        let [x, x2, y, y2] = area.lrtb();
+        for x in x..x2.saturating_sub(1) {
+            to.blit(&Self::N, x, y, style);
+            to.blit(&Self::S, x, y2.saturating_sub(1), style)
+        }
+        Ok(area)
+    }
+    #[inline] fn draw_vertical (
+        &self, to: &mut TuiOut, style: Option<Style>
+    ) -> Usually<[u16;4]> {
+        let area = to.area();
+        let style = style.or_else(||self.style_vertical());
+        let [x, x2, y, y2] = area.lrtb();
+        let h = y2 - y;
+        if h > 1 {
+            for y in y..y2.saturating_sub(1) {
+                to.blit(&Self::W, x, y, style);
+                to.blit(&Self::E, x2.saturating_sub(1), y, style);
+            }
+        } else if h > 0 {
+            to.blit(&Self::W0, x, y, style);
+            to.blit(&Self::E0, x2.saturating_sub(1), y, style);
+        }
+        Ok(area)
+    }
+    #[inline] fn draw_corners (
+        &self, to: &mut TuiOut, style: Option<Style>
+    ) -> Usually<[u16;4]> {
+        let area = to.area();
+        let style = style.or_else(||self.style_corners());
+        let [x, y, width, height] = area.xywh();
+        if width > 1 && height > 1 {
+            to.blit(&Self::NW, x, y, style);
+            to.blit(&Self::NE, x + width - 1, y, style);
+            to.blit(&Self::SW, x, y + height - 1, style);
+            to.blit(&Self::SE, x + width - 1, y + height - 1, style);
+        }
+        Ok(area)
+    }
+    #[inline] fn style            (&self) -> Option<Style> { None }
+    #[inline] fn style_horizontal (&self) -> Option<Style> { self.style() }
+    #[inline] fn style_vertical   (&self) -> Option<Style> { self.style() }
+    #[inline] fn style_corners    (&self) -> Option<Style> { self.style() }
+}