diff --git a/output/src/out_impls.rs b/output/src/out_impls.rs
index 5b160ca..2799859 100644
--- a/output/src/out_impls.rs
+++ b/output/src/out_impls.rs
@@ -64,8 +64,8 @@ impl<N: Coord> XYWH<N> {
     pub fn with_h (&self, h: N) -> XYWH<N> {
         Self(self.x(), self.y(), self.w(), h)
     }
-    pub fn lrtb (&self) -> XYWH<N> {
-        Self(self.x(), self.x2(), self.y(), self.y2())
+    pub fn lrtb (&self) -> [N;4] {
+        [self.x(), self.x2(), self.y(), self.y2()]
     }
     pub fn clipped_w (&self, w: N) -> XYWH<N> {
         Self(self.x(), self.y(), self.w().min(w), self.h())
diff --git a/tui/src/lib.rs b/tui/src/lib.rs
index ee26633..16fd3d7 100644
--- a/tui/src/lib.rs
+++ b/tui/src/lib.rs
@@ -1,7 +1,6 @@
 #![feature(type_changing_struct_update, trait_alias)]
 
-use std::{time::Duration, thread::{spawn, JoinHandle}};
-
+use std::{time::Duration, thread::{spawn, JoinHandle}, io::Write};
 use unicode_width::*;
 
 pub use ::{
@@ -86,7 +85,9 @@ mod tui_traits;   pub use self::tui_traits::*;
 mod tui_impls;    pub use self::tui_impls::*;
 
 /// Run an app in the main loop.
-pub fn tui_run <T>(state: &Arc<RwLock<T>>) -> Usually<Arc<RwLock<Tui>>> {
+pub fn tui_run <T: Send + Sync + Draw<TuiOut> + Handle<TuiIn> + 'static> (
+    state: &Arc<RwLock<T>>
+) -> Usually<Arc<RwLock<Tui>>> {
     let backend = CrosstermBackend::new(stdout());
     let Size { width, height } = backend.size()?;
     let tui = Arc::new(RwLock::new(Tui {
@@ -96,9 +97,9 @@ pub fn tui_run <T>(state: &Arc<RwLock<T>>) -> Usually<Arc<RwLock<Tui>>> {
         perf:    Default::default(),
         backend,
     }));
-    let _input_thread = tui_input(tui, state, Duration::from_millis(100));
+    let _input_thread = tui_input(tui.clone(), state, Duration::from_millis(100));
     tui.write().unwrap().setup()?;
-    let render_thread = tui_output(tui, state, Duration::from_millis(10))?;
+    let render_thread = tui_output(tui.clone(), state, Duration::from_millis(10))?;
     match render_thread.join() {
         Ok(result) => {
             tui.write().unwrap().teardown()?;
@@ -112,7 +113,9 @@ pub fn tui_run <T>(state: &Arc<RwLock<T>>) -> Usually<Arc<RwLock<Tui>>> {
     Ok(tui)
 }
 
-pub fn tui_setup (backend: &mut CrosstermBackend) -> Usually<()> {
+pub fn tui_setup <W: Write> (
+    backend: &mut CrosstermBackend<W>
+) -> 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();
@@ -125,14 +128,14 @@ pub fn tui_setup (backend: &mut CrosstermBackend) -> Usually<()> {
     enable_raw_mode().map_err(Into::into)
 }
 
-pub fn tui_teardown (backend: &mut CrosstermBackend) -> Usually<()> {
+pub fn tui_teardown <W: Write> (backend: &mut CrosstermBackend<W>) -> Usually<()> {
     stdout().execute(LeaveAlternateScreen)?;
     backend.show_cursor()?;
     disable_raw_mode().map_err(Into::into)
 }
 
-pub fn tui_resized (
-    backend: &mut CrosstermBackend, buffer: &mut Buffer, size: ratatui::prelude::Rect
+pub fn tui_resized <W: Write> (
+    backend: &mut CrosstermBackend<W>, buffer: &mut Buffer, size: ratatui::prelude::Rect
 ) {
     if buffer.area != size {
         backend.clear_region(ClearType::All).unwrap();
@@ -141,17 +144,21 @@ pub fn tui_resized (
     }
 }
 
-pub fn tui_redrawn (
-    backend: &mut CrosstermBackend, buffer: &mut Buffer, new_buffer: &mut Buffer
+pub fn tui_redrawn <'b, W: Write> (
+    backend: &mut CrosstermBackend<W>,
+    mut prev_buffer: &'b mut Buffer,
+    mut next_buffer: &'b mut Buffer
 ) {
-    let updates = buffer.diff(&new_buffer);
+    let updates = prev_buffer.diff(&next_buffer);
     backend.draw(updates.into_iter()).expect("failed to render");
-    backend.flush().expect("failed to flush output new_buffer");
-    std::mem::swap(&mut buffer, &mut new_buffer);
-    new_buffer.reset();
+    Backend::flush(backend).expect("failed to flush output new_buffer");
+    std::mem::swap(&mut prev_buffer, &mut next_buffer);
+    next_buffer.reset();
 }
 
-pub fn tui_update (buf: &mut Buffer, area: XY<u16>, callback: &impl Fn(&mut Cell, u16, u16)) {
+pub fn tui_update (
+    buf: &mut Buffer, area: XYWH<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() {
@@ -167,7 +174,7 @@ pub fn tui_update (buf: &mut Buffer, area: XY<u16>, callback: &impl Fn(&mut Cell
 
 /// Spawn the output thread.
 pub fn tui_output <T: Draw<TuiOut> + Send + Sync + 'static> (
-    engine: &Arc<RwLock<Tui>>, state: &Arc<RwLock<T>>, timer: Duration
+    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();
@@ -202,7 +209,7 @@ pub fn tui_output <T: Draw<TuiOut> + Send + Sync + 'static> (
 
 /// Spawn the input thread.
 pub fn tui_input <T: Handle<TuiIn> + Send + Sync + 'static> (
-    engine: &Arc<RwLock<Tui>>, state: &Arc<RwLock<T>>, timer: Duration
+    engine: Arc<RwLock<Tui>>, state: &Arc<RwLock<T>>, timer: Duration
 ) -> JoinHandle<()> {
     let exited = engine.read().unwrap().exited.clone();
     let state  = state.clone();
diff --git a/tui/src/tui_impls.rs b/tui/src/tui_impls.rs
index e29529a..c6c4afa 100644
--- a/tui/src/tui_impls.rs
+++ b/tui/src/tui_impls.rs
@@ -4,7 +4,11 @@ use rand::{thread_rng, distributions::uniform::UniformSampler};
 
 impl Tui {
     /// Create and launch a terminal user interface.
-    pub fn run <T> (state: &Arc<RwLock<T>>) -> Usually<Arc<RwLock<Self>>> { tui_run(state) }
+    pub fn run <T: Send + Sync + Handle<TuiIn> + Draw<TuiOut> + 'static> (
+        state: &Arc<RwLock<T>>
+    ) -> Usually<Arc<RwLock<Self>>> {
+        tui_run(state)
+    }
     /// True if done
     pub fn exited (&self) -> bool { self.exited.fetch_and(true, Relaxed) }
     /// Prepare before run
@@ -97,22 +101,22 @@ impl Out for TuiOut {
     }
 }
 impl TuiOut {
-    #[inline] pub fn with_rect (&mut self, area: XY<u16>) -> &mut Self { self.area = area; self }
-    pub fn update    (&mut self, area: XY<u16>, callback: &impl Fn(&mut Cell, u16, u16)) { tui_update(&mut self.buffer, area, callback); }
-    pub fn fill_char (&mut self, area: XY<u16>, c: char) { self.update(area, &|cell,_,_|{cell.set_char(c);}) }
-    pub fn fill_bg   (&mut self, area: XY<u16>, color: Color) { self.update(area, &|cell,_,_|{cell.set_bg(color);}) }
-    pub fn fill_fg   (&mut self, area: XY<u16>, color: Color) { self.update(area, &|cell,_,_|{cell.set_fg(color);}) }
-    pub fn fill_mod  (&mut self, area: XY<u16>, on: bool, modifier: Modifier) {
+    #[inline] pub fn with_rect (&mut self, area: XYWH<u16>) -> &mut Self { self.area = area; self }
+    pub fn update    (&mut self, area: XYWH<u16>, callback: &impl Fn(&mut Cell, u16, u16)) { tui_update(&mut self.buffer, area, callback); }
+    pub fn fill_char (&mut self, area: XYWH<u16>, c: char) { self.update(area, &|cell,_,_|{cell.set_char(c);}) }
+    pub fn fill_bg   (&mut self, area: XYWH<u16>, color: Color) { self.update(area, &|cell,_,_|{cell.set_bg(color);}) }
+    pub fn fill_fg   (&mut self, area: XYWH<u16>, color: Color) { self.update(area, &|cell,_,_|{cell.set_fg(color);}) }
+    pub fn fill_mod  (&mut self, area: XYWH<u16>, on: bool, modifier: Modifier) {
         if on {
             self.update(area, &|cell,_,_|cell.modifier.insert(modifier))
         } else {
             self.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>) {
+    pub fn fill_bold        (&mut self, area: XYWH<u16>, on: bool) { self.fill_mod(area, on, Modifier::BOLD) }
+    pub fn fill_reversed    (&mut self, area: XYWH<u16>, on: bool) { self.fill_mod(area, on, Modifier::REVERSED) }
+    pub fn fill_crossed_out (&mut self, area: XYWH<u16>, on: bool) { self.fill_mod(area, on, Modifier::CROSSED_OUT) }
+    pub fn fill_ul (&mut self, area: XYWH<u16>, color: Option<Color>) {
         if let Some(color) = color {
             self.update(area, &|cell,_,_|{
                 cell.modifier.insert(ratatui::prelude::Modifier::UNDERLINED);
@@ -282,11 +286,11 @@ impl<T> Phat<T> {
     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)))
+        Fixed::Y(1, Tui::fg_bg(fg, bg, Repeat::X(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)))
+        Fixed::Y(1, Tui::fg_bg(fg, bg, Repeat::X(Self::HI)))
     }
 }
 impl Scrollbar {
@@ -350,14 +354,30 @@ mod layout {
     impl<T: Content<TuiOut>> Layout<TuiOut> for Modify<T> {}
     impl<T: Content<TuiOut>> Layout<TuiOut> for Styled<T> {}
     impl Layout<TuiOut> for Repeat<'_> {}
-    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) } }
+    impl Layout<TuiOut> for &str {
+        fn layout (&self, to: XYWH<u16>) -> XYWH<u16> {
+            to.centered_xy([width_chars_max(to.w(), self), 1])
+        }
+    }
+    impl Layout<TuiOut> for String {
+        fn layout (&self, to: XYWH<u16>) -> XYWH<u16> {
+            self.as_str().layout(to)
+        }
+    }
+    impl Layout<TuiOut> for Arc<str> {
+        fn layout (&self, to: XYWH<u16>) -> XYWH<u16> {
+            self.as_ref().layout(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) } 
+        fn layout (&self, to: XYWH<u16>) -> XYWH<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()] }
+        fn layout (&self, to: XYWH<u16>) -> XYWH<u16> {
+            XYWH(to.x(), to.y(), to.w().min(self.0).min(self.1.as_ref().width() as u16), to.h())
+        }
     }
 }
 
@@ -394,9 +414,9 @@ mod draw {
 
     impl Draw<TuiOut> for Repeat<'_> {
         fn draw (&self, to: &mut TuiOut) {
+            let XYWH(x, y, w, h) = to.area();
             match self {
                 Self::X(c) => {
-                    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(&c);
@@ -404,21 +424,19 @@ mod draw {
                     }
                 },
                 Self::Y(c) => {
-                    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(&c);
                         }
                     }
                 },
-                Self::XY => {
-                    let [x, y, w, h] = to.area().xywh();
-                    let a = self.0.len();
+                Self::XY(c) => {
+                    let a = c.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]);
+                                cell.set_symbol(&c[u..u+1]);
                             }
                         }
                     }
@@ -429,7 +447,7 @@ mod draw {
 
     impl Draw<TuiOut> for Scrollbar {
         fn draw (&self, to: &mut TuiOut) {
-            let [x1, y1, w, h] = to.area().xywh();
+            let XYWH(x1, y1, w, h) = to.area();
             match self {
                 Self::X { .. } => {
                     let x2 = x1 + w;
@@ -439,10 +457,10 @@ mod draw {
                                 cell.set_fg(Rgb(255, 255, 255));
                                 cell.set_bg(Rgb(0, 0, 0));
                                 cell.set_char(Self::ICON_DEC_H[i as usize]);
-                            } else if i > (w as usize - Self::ICON_INC.len()) {
+                            } else if i > (w as usize - Self::ICON_INC_H.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]);
+                                cell.set_char(Self::ICON_INC_H[w as usize - i]);
                             } else if false {
                                 cell.set_fg(Rgb(255, 255, 255));
                                 cell.set_bg(Reset);
@@ -462,11 +480,11 @@ mod draw {
                             if (i as usize) < (Self::ICON_DEC_V.len()) {
                                 cell.set_fg(Rgb(255, 255, 255));
                                 cell.set_bg(Rgb(0, 0, 0));
-                                cell.set_char(Self::ICON_DEC_v[i as usize]);
-                            } else if (i as usize) > (h as usize - Self::ICON_INC.len()) {
+                                cell.set_char(Self::ICON_DEC_V[i as usize]);
+                            } else if (i as usize) > (h as usize - Self::ICON_INC_V.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]);
+                                cell.set_char(Self::ICON_INC_V[h as usize - i]);
                             } else if false {
                                 cell.set_fg(Rgb(255, 255, 255));
                                 cell.set_bg(Reset);
@@ -485,7 +503,7 @@ mod draw {
 
     impl Draw<TuiOut> for &str {
         fn draw (&self, to: &mut TuiOut) {
-            let [x, y, w, ..] = self.layout(to.area());
+            let XYWH(x, y, w, ..) = self.layout(to.area());
             to.text(&self, x, y, w)
         }
     }
diff --git a/tui/src/tui_structs.rs b/tui/src/tui_structs.rs
index 57337b5..e0eebbc 100644
--- a/tui/src/tui_structs.rs
+++ b/tui/src/tui_structs.rs
@@ -22,7 +22,10 @@ pub struct Tui {
 
 #[derive(Debug, Clone, Eq, PartialEq, PartialOrd)] pub struct TuiEvent(pub Event);
 
-pub struct TuiKey(Option<KeyCode>, KeyModifiers);
+#[derive(Debug, Clone, Eq, PartialEq, PartialOrd)] pub struct TuiKey(
+    pub Option<KeyCode>,
+    pub KeyModifiers
+);
 
 #[derive(Default)] pub struct TuiOut {
     pub buffer: Buffer,
@@ -68,8 +71,8 @@ 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 std::marker::PhantomData<O>,
+    pub Perhaps<T>
 );
 
 /// Repeat a string, e.g. for background
diff --git a/tui/src/tui_traits.rs b/tui/src/tui_traits.rs
index 0520edd..77276c7 100644
--- a/tui/src/tui_traits.rs
+++ b/tui/src/tui_traits.rs
@@ -58,7 +58,7 @@ pub trait BorderStyle: Content<TuiOut> + Copy {
     }
     #[inline] fn draw_horizontal (
         &self, to: &mut TuiOut, style: Option<Style>
-    ) -> Usually<[u16;4]> {
+    ) -> Usually<XYWH<u16>> {
         let area = to.area();
         let style = style.or_else(||self.style_horizontal());
         let [x, x2, y, y2] = area.lrtb();
@@ -70,7 +70,7 @@ pub trait BorderStyle: Content<TuiOut> + Copy {
     }
     #[inline] fn draw_vertical (
         &self, to: &mut TuiOut, style: Option<Style>
-    ) -> Usually<[u16;4]> {
+    ) -> Usually<XYWH<u16>> {
         let area = to.area();
         let style = style.or_else(||self.style_vertical());
         let [x, x2, y, y2] = area.lrtb();
@@ -88,10 +88,10 @@ pub trait BorderStyle: Content<TuiOut> + Copy {
     }
     #[inline] fn draw_corners (
         &self, to: &mut TuiOut, style: Option<Style>
-    ) -> Usually<[u16;4]> {
+    ) -> Usually<XYWH<u16>> {
         let area = to.area();
         let style = style.or_else(||self.style_corners());
-        let [x, y, width, height] = area.xywh();
+        let XYWH(x, y, width, height) = area;
         if width > 1 && height > 1 {
             to.blit(&Self::NW, x, y, style);
             to.blit(&Self::NE, x + width - 1, y, style);