diff --git a/crates/tek_core/src/render_collect.rs b/crates/tek_core/src/collect.rs
similarity index 54%
rename from crates/tek_core/src/render_collect.rs
rename to crates/tek_core/src/collect.rs
index af37753f..e89e5b6f 100644
--- a/crates/tek_core/src/render_collect.rs
+++ b/crates/tek_core/src/collect.rs
@@ -1,11 +1,11 @@
 use crate::*;
 
 pub enum Collected<'a, T, U> {
-    Box(Box<dyn Render<'a, T, U> + 'a>),
-    Ref(&'a (dyn Render<'a, T, U> + 'a)),
+    Box(Box<dyn Render<T, U> + 'a>),
+    Ref(&'a (dyn Render<T, U> + 'a)),
 }
-impl<'a, T, U> Render<'a, T, U> for Collected<'a, T, U> {
-    fn render (&self, to: &'a mut T) -> Perhaps<U> {
+impl<'a, T, U> Render<T, U> for Collected<'a, T, U> {
+    fn render (&self, to: &mut T) -> Perhaps<U> {
         match self {
             Self::Box(item) => (*item).render(to),
             Self::Ref(item) => (*item).render(to),
@@ -21,20 +21,20 @@ impl<'a, T, U> Collection<'a, T, U> {
     }
 }
 pub trait Collect<'a, T, U> {
-    fn add_box (self, item: Box<dyn Render<'a, T, U> + 'a>) -> Self;
-    fn add_ref (self, item: &'a dyn Render<'a, T, U>) -> Self;
-    fn add <R: Render<'a, T, U> + Sized + 'a> (self, item: R) -> Self
+    fn add_box (self, item: Box<dyn Render<T, U> + 'a>) -> Self;
+    fn add_ref (self, item: &'a dyn Render<T, U>) -> Self;
+    fn add <R: Render<T, U> + Sized + 'a> (self, item: R) -> Self
         where Self: Sized
     {
         self.add_box(Box::new(item))
     }
 }
 impl<'a, T, U> Collect<'a, T, U> for Collection<'a, T, U> {
-    fn add_box (mut self, item: Box<dyn Render<'a, T, U> + 'a>) -> Self {
+    fn add_box (mut self, item: Box<dyn Render<T, U> + 'a>) -> Self {
         self.0.push(Collected::Box(item));
         self
     }
-    fn add_ref (mut self, item: &'a dyn Render<'a, T, U>) -> Self {
+    fn add_ref (mut self, item: &'a dyn Render<T, U>) -> Self {
         self.0.push(Collected::Ref(item));
         self
     }
diff --git a/crates/tek_core/src/handle.rs b/crates/tek_core/src/handle.rs
index 72ea71f6..bcbf14ca 100644
--- a/crates/tek_core/src/handle.rs
+++ b/crates/tek_core/src/handle.rs
@@ -2,17 +2,17 @@ use crate::*;
 
 /// Handle input
 pub trait Handle<T, U>: Send + Sync {
-    fn handle (&mut self, context: &mut T) -> Perhaps<U>;
+    fn handle (&mut self, context: &T) -> Perhaps<U>;
 }
 
 impl<H, T, U> Handle<T, U> for &mut H where H: Handle<T, U> {
-    fn handle (&mut self, context: &mut T) -> Perhaps<U> {
+    fn handle (&mut self, context: &T) -> Perhaps<U> {
         (*self).handle(context)
     }
 }
 
 impl<H, T, U> Handle<T, U> for Option<H> where H: Handle<T, U> {
-    fn handle (&mut self, context: &mut T) -> Perhaps<U> {
+    fn handle (&mut self, context: &T) -> Perhaps<U> {
         if let Some(ref mut handle) = self {
             handle.handle(context)
         } else {
@@ -22,25 +22,25 @@ impl<H, T, U> Handle<T, U> for Option<H> where H: Handle<T, U> {
 }
 
 impl<H, T, U> Handle<T, U> for Mutex<H> where H: Handle<T, U> {
-    fn handle (&mut self, context: &mut T) -> Perhaps<U> {
+    fn handle (&mut self, context: &T) -> Perhaps<U> {
         self.lock().unwrap().handle(context)
     }
 }
 
 impl<H, T, U> Handle<T, U> for Arc<Mutex<H>> where H: Handle<T, U> {
-    fn handle (&mut self, context: &mut T) -> Perhaps<U> {
+    fn handle (&mut self, context: &T) -> Perhaps<U> {
         self.lock().unwrap().handle(context)
     }
 }
 
 impl<H, T, U> Handle<T, U> for RwLock<H> where H: Handle<T, U> {
-    fn handle (&mut self, context: &mut T) -> Perhaps<U> {
+    fn handle (&mut self, context: &T) -> Perhaps<U> {
         self.write().unwrap().handle(context)
     }
 }
 
 impl<H, T, U> Handle<T, U> for Arc<RwLock<H>> where H: Handle<T, U> {
-    fn handle (&mut self, context: &mut T) -> Perhaps<U> {
+    fn handle (&mut self, context: &T) -> Perhaps<U> {
         self.write().unwrap().handle(context)
     }
 }
diff --git a/crates/tek_core/src/jack_core.rs b/crates/tek_core/src/jack_core.rs
index b085fbbd..1f7823ff 100644
--- a/crates/tek_core/src/jack_core.rs
+++ b/crates/tek_core/src/jack_core.rs
@@ -1,18 +1,18 @@
 use crate::{*, jack::*};
 
 /// A UI component that may be associated with a JACK client by the `Jack` factory.
-pub trait Device<'a, T, U>: Render<'a, T, U> + Handle + Process + Send + Sync {
+pub trait Device<E: Engine>: Component<E> + Process {
     /// Perform type erasure for collecting heterogeneous devices.
-    fn boxed (self) -> Box<dyn Device<'a, T, U>> where Self: Sized + 'static {
+    fn boxed (self) -> Box<dyn Device<E>> where Self: Sized + 'static {
         Box::new(self)
     }
 }
 
 /// All things that implement the required traits can be treated as `Device`.
-impl<'a, D, T, U> Device<'a, T, U> for D where D: Render<'a, T, U> + Handle + Process {}
+impl<D, E: Engine> Device<E> for D where D: Component<E> + Process {}
 
-impl<'a, T, U> Render<'a, T, U> for Box<dyn Device<'a, T, U>> {
-    fn render (&self, to: &'a mut T) -> Result<Option<U>, Box<dyn std::error::Error>> {
+impl<E: Engine> Render<E, E::Rendered> for Box<dyn Device<E>> {
+    fn render (&self, to: &mut E) -> Perhaps<E::Rendered> {
         (**self).render(to)
     }
 }
@@ -98,8 +98,8 @@ pub trait Process {
 }
 
 /// Just run thing with JACK. Returns the activated client.
-pub fn jack_run <T> (name: &str, app: &Arc<RwLock<T>>) -> Usually<DynamicAsyncClient>
-    where T: Handle + Process + Send + Sync + 'static
+pub fn jack_run <T, E: Engine> (name: &str, app: &Arc<RwLock<T>>) -> Usually<DynamicAsyncClient>
+    where T: Handle<E, E::Handled> + Process + Send + Sync + 'static
 {
     let options = ClientOptions::NO_START_SERVER;
     let (client, _status) = Client::new(name, options)?;
@@ -143,12 +143,11 @@ impl Jack {
             )?.0,
         })
     }
-    pub fn run <'a: 'static, D, T, U> (
+    pub fn run <'a: 'static, D, E> (
         self, state: impl FnOnce(JackPorts)->Box<D>
-    ) -> Usually<JackDevice<'a, T, U>>
-        where D: Device<'a, T, U> + Process + Sized + 'static,
-              T: 'static,
-              U: 'static
+    ) -> Usually<JackDevice<E>>
+        where D: Device<E> + Sized + 'static,
+              E: Engine + 'static,
     {
         let owned_ports = JackPorts {
             audio_ins:  register_ports(&self.client, self.audio_ins,  AudioIn)?,
@@ -164,7 +163,7 @@ impl Jack {
             .map(|p|Ok(p.name()?)).collect::<Usually<Vec<_>>>()?;
         let audio_ins = owned_ports.audio_ins.values()
             .map(|p|Ok(p.name()?)).collect::<Usually<Vec<_>>>()?;
-        let state = Arc::new(RwLock::new(state(owned_ports) as Box<dyn Device<T, U>>));
+        let state = Arc::new(RwLock::new(state(owned_ports) as Box<dyn Device<E>>));
         let client = self.client.activate_async(
             Notifications(Box::new({
                 let _state = state.clone();
diff --git a/crates/tek_core/src/jack_device.rs b/crates/tek_core/src/jack_device.rs
index 4eb5873c..d4984f30 100644
--- a/crates/tek_core/src/jack_device.rs
+++ b/crates/tek_core/src/jack_device.rs
@@ -1,31 +1,31 @@
 use crate::{*, jack::*};
 
 /// A [Device] bound to a JACK client and a set of ports.
-pub struct JackDevice<'a, T, U> {
+pub struct JackDevice<E: Engine> {
     /// The active JACK client of this device.
     pub client: DynamicAsyncClient,
     /// The device state, encapsulated for sharing between threads.
-    pub state:  Arc<RwLock<Box<dyn Device<'a, T, U>>>>,
+    pub state:  Arc<RwLock<Box<dyn Device<E>>>>,
     /// Unowned copies of the device's JACK ports, for connecting to the device.
     /// The "real" readable/writable `Port`s are owned by the `state`.
     pub ports:  UnownedJackPorts,
 }
-impl<'a, T, U> std::fmt::Debug for JackDevice<'a, T, U> {
+impl<E: Engine> std::fmt::Debug for JackDevice<E> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.debug_struct("JackDevice").field("ports", &self.ports).finish()
     }
 }
-impl<'a, T, U> Render<'a, T, U> for JackDevice<'a, T, U> {
-    fn render (&self, to: &'a mut T) -> Perhaps<U> {
+impl<E: Engine> Render<E, E::Rendered> for JackDevice<E> {
+    fn render (&self, to: &mut E) -> Perhaps<E::Rendered> {
         self.state.read().unwrap().render(to)
     }
 }
-impl<'a, T, U> Handle for JackDevice<'a, T, U> {
-    fn handle (&mut self, event: &AppEvent) -> Usually<bool> {
-        self.state.write().unwrap().handle(event)
+impl<E: Engine> Handle<E, E::Handled> for JackDevice<E> {
+    fn handle (&mut self, from: &E) -> Perhaps<E::Handled> {
+        self.state.write().unwrap().handle(from)
     }
 }
-impl<'a, T, U> Ports for JackDevice<'a, T, U> {
+impl<E: Engine> Ports for JackDevice<E> {
     fn audio_ins (&self) -> Usually<Vec<&Port<Unowned>>> {
         Ok(self.ports.audio_ins.values().collect())
     }
@@ -39,13 +39,13 @@ impl<'a, T, U> Ports for JackDevice<'a, T, U> {
         Ok(self.ports.midi_outs.values().collect())
     }
 }
-impl<'a, T, U> JackDevice<'a, T, U> {
+impl<E: Engine> JackDevice<E> {
     /// Returns a locked mutex of the state's contents.
-    pub fn state (&self) -> LockResult<RwLockReadGuard<Box<dyn Device<'a, T, U>>>> {
+    pub fn state (&self) -> LockResult<RwLockReadGuard<Box<dyn Device<E>>>> {
         self.state.read()
     }
     /// Returns a locked mutex of the state's contents.
-    pub fn state_mut (&self) -> LockResult<RwLockWriteGuard<Box<dyn Device<'a, T, U>>>> {
+    pub fn state_mut (&self) -> LockResult<RwLockWriteGuard<Box<dyn Device<E>>>> {
         self.state.write()
     }
     pub fn connect_midi_in (&self, index: usize, port: &Port<Unowned>) -> Usually<()> {
diff --git a/crates/tek_core/src/lib.rs b/crates/tek_core/src/lib.rs
index 3bd674c4..83f73d12 100644
--- a/crates/tek_core/src/lib.rs
+++ b/crates/tek_core/src/lib.rs
@@ -27,6 +27,7 @@ use better_panic::{Settings, Verbosity};
 }
 
 submod! {
+    collect
     component
     edn
     engine
@@ -42,7 +43,6 @@ submod! {
     render
     render_axis
     render_buffer
-    render_collect
     render_layered
     render_split
     time
diff --git a/crates/tek_core/src/render.rs b/crates/tek_core/src/render.rs
index 1cef9691..0a61678a 100644
--- a/crates/tek_core/src/render.rs
+++ b/crates/tek_core/src/render.rs
@@ -2,7 +2,7 @@ use crate::*;
 
 /// Render to output.
 pub trait Render<T, U>: Send + Sync {
-    fn render (&self, context: &mut T) -> Perhaps<U>;
+    fn render (&self, to: &mut T) -> Perhaps<U>;
 }
 
 /// Options can be rendered optionally.
diff --git a/crates/tek_core/src/render_layered.rs b/crates/tek_core/src/render_layered.rs
index ad4abc17..c3ef8236 100644
--- a/crates/tek_core/src/render_layered.rs
+++ b/crates/tek_core/src/render_layered.rs
@@ -20,7 +20,7 @@ impl<'a, T, U> Collect<'a, T, U> for Layered<'a, T, U> {
 }
 
 impl<'a> Render<TuiContext, Rect> for Layered<'a, TuiContext, Rect> {
-    fn render (&self, to: &mut impl TuiTarget) -> Perhaps<Rect> {
+    fn render (&self, to: &mut TuiContext) -> Perhaps<Rect> {
         let area = to.area();
         for layer in self.0.0.iter() {
             layer.render(to)?;
diff --git a/crates/tek_core/src/render_split.rs b/crates/tek_core/src/render_split.rs
index dc107c8c..f857929a 100644
--- a/crates/tek_core/src/render_split.rs
+++ b/crates/tek_core/src/render_split.rs
@@ -44,24 +44,24 @@ impl<'a, T, U> Split<'a, T, U> {
 }
 
 impl<'a, T, U> Collect<'a, T, U> for Split<'a, T, U> {
-    fn add_box (mut self, item: Box<dyn Render<'a, T, U> + 'a>) -> Self {
+    fn add_box (mut self, item: Box<dyn Render<T, U> + 'a>) -> Self {
         self.items = self.items.add_box(item);
         self
     }
-    fn add_ref (mut self, item: &'a dyn Render<'a, T, U>) -> Self {
+    fn add_ref (mut self, item: &'a dyn Render<T, U>) -> Self {
         self.items = self.items.add_ref(item);
         self
     }
 }
 
-impl<'a> Render<'a, TuiOutput<'a>, Rect> for Split<'a, TuiOutput<'a>, Rect> {
-    fn render (&self, to: &mut TuiOutput<'a>) -> Perhaps<Rect> {
+impl<'a> Render<TuiContext, Rect> for Split<'a, TuiContext, Rect> {
+    fn render (&self, to: &mut TuiContext) -> Perhaps<Rect> {
         Ok(None)//Rect::default())//Some(self.render_areas(to)?.0))
     }
 }
 
-impl<'a, 'b: 'a> Split<'a, TuiOutput<'a>, Rect> {
-    pub fn render_areas (&'a self, to: &mut TuiOutput<'a>) -> Usually<(Rect, Vec<Rect>)> {
+impl<'a> Split<'a, TuiContext, Rect> {
+    pub fn render_areas (&self, to: &mut TuiContext) -> Usually<(Rect, Vec<Rect>)> {
         Ok((Rect::default(), vec![]))
         //let Rect { mut x, mut y, mut width, mut height } = to.area;
         //let TuiOutput { buffer, area } = to;
diff --git a/crates/tek_core/src/tui.rs b/crates/tek_core/src/tui.rs
index 32607bf3..4681164e 100644
--- a/crates/tek_core/src/tui.rs
+++ b/crates/tek_core/src/tui.rs
@@ -34,24 +34,22 @@ impl Engine for TuiContext {
     fn teardown (&mut self) -> Usually<()> {
         terminal_teardown()
     }
-    fn handle (&mut self, state: &mut impl Handle<Self, bool>) -> Usually<()> {
+    fn handle (&self, state: &mut impl Handle<Self, bool>) -> Usually<()> {
         if ::crossterm::event::poll(self.poll).is_ok() {
             let event = ::crossterm::event::read().unwrap();
             if let Event::Key(KeyEvent {
                 code: KeyCode::Char('c'), modifiers: KeyModifiers::CONTROL, ..
             }) = event {
                 self.exited.store(true, Ordering::Relaxed);
-            } else if let Err(e) = state.handle(&mut self) {
+            } else if let Err(e) = state.handle(self) {
                 panic!("{e}")
             }
         }
         Ok(())
     }
     fn render (&mut self, state: &impl Render<Self, Rect>) -> Usually<()> {
-        if let Ok(state) = state.try_read() {
-            state.render(&mut self).expect("render failed");
-        }
-        std::thread::sleep(self.sleep)
+        state.render(self).expect("render failed");
+        Ok(())
     }
 }
 impl TuiContext {
@@ -61,7 +59,7 @@ impl TuiContext {
     ) -> Usually<Arc<RwLock<R>>> {
         let backend = CrosstermBackend::new(stdout());
         let area    = backend.size()?;
-        let engine  = Arc::new(Self {
+        let engine  = Arc::new(RwLock::new(Self {
             sleep:   Duration::from_millis(20),
             poll:    Duration::from_millis(100),
             exited:  Arc::new(AtomicBool::new(false)),
@@ -69,25 +67,30 @@ impl TuiContext {
             buffers: [Buffer::empty(area), Buffer::empty(area)],
             backend,
             area,
-        });
+        }));
         let _input_thread = {
             let engine = engine.clone();
             let state  = state.clone();
             spawn(move || loop {
+                let engine = engine.read().unwrap();
                 if engine.exited() {
                     break
                 }
-                engine.handle(&mut state).expect("handle failed");
+                engine.handle(&mut *state.write().unwrap()).expect("handle failed");
             })
         };
         let main_thread = {
             let engine = engine.clone();
             let state  = state.clone();
             spawn(move || loop {
+                let mut engine = engine.write().unwrap();
                 if engine.exited() {
                     break
                 }
-                engine.render(&mut state).expect("render failed");
+                if let Ok(state) = state.try_read() {
+                    engine.render(&*state).expect("render failed");
+                }
+                std::thread::sleep(engine.sleep);
             })
         };
         main_thread.join().expect("main thread failed");
@@ -248,15 +251,17 @@ pub trait BorderStyle {
     const W:  &'static str = "";
 
     #[inline]
-    fn draw <'a> (&self, to: &mut TuiOutput<'a>) -> Perhaps<Rect> {
-        self.draw_horizontal(to.buffer, to.area, None)?;
-        self.draw_vertical(to.buffer, to.area, None)?;
-        self.draw_corners(to.buffer, to.area, None)?;
+    fn draw <'a> (&self, to: &mut TuiContext) -> Perhaps<Rect> {
+        self.draw_horizontal(to, None)?;
+        self.draw_vertical(to, None)?;
+        self.draw_corners(to, None)?;
         Ok(Some(to.area))
     }
 
     #[inline]
-    fn draw_horizontal (&self, buf: &mut Buffer, area: Rect, style: Option<Style>) -> Usually<Rect> {
+    fn draw_horizontal (&self, to: &mut TuiContext, style: Option<Style>) -> Usually<Rect> {
+        let area = to.area();
+        let buf = to.buffer();
         let style = style.or_else(||self.style_horizontal());
         for x in area.x..(area.x+area.width).saturating_sub(1) {
             self.draw_north(buf, x, area.y, style)?;
@@ -274,7 +279,9 @@ pub trait BorderStyle {
     }
 
     #[inline]
-    fn draw_vertical (&self, buf: &mut Buffer, area: Rect, style: Option<Style>) -> Usually<Rect> {
+    fn draw_vertical (&self, to: &mut TuiContext, style: Option<Style>) -> Usually<Rect> {
+        let area = to.area();
+        let buf = to.buffer();
         let style = style.or_else(||self.style_vertical());
         for y in area.y..(area.y+area.height).saturating_sub(1) {
             Self::W.blit(buf, area.x, y, style)?;
@@ -284,7 +291,9 @@ pub trait BorderStyle {
     }
 
     #[inline]
-    fn draw_corners (&self, buf: &mut Buffer, area: Rect, style: Option<Style>) -> Usually<Rect> {
+    fn draw_corners (&self, to: &mut TuiContext, style: Option<Style>) -> Usually<Rect> {
+        let area = to.area();
+        let buf = to.buffer();
         let style = style.or_else(||self.style_corners());
         if area.width > 0 && area.height > 0 {
             Self::NW.blit(buf, area.x, area.y, style)?;