diff --git a/src/main.rs b/src/main.rs
index b95658d..c871e1e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,8 +1,12 @@
 use std::rc::Rc;
-use slint::{Color, VecModel};
+use std::thread;
+use std::time::Duration;
+use slint::{Color, Timer, TimerMode, VecModel};
 
 slint::include_modules!();
 
+/// Zet HSL (hue/saturation/lightness) om naar RGB (u8).
+/// `hue` in graden (0-360), `sat` en `light` als fractie (0-1).
 fn hsl_to_rgb(hue: f32, sat: f32, light: f32) -> (u8, u8, u8) {
     let c = (1.0 - (2.0 * light - 1.0).abs()) * sat;
     let x = c * (1.0 - ((hue / 60.0) % 2.0 - 1.0).abs());
@@ -24,20 +28,54 @@ fn hsl_to_rgb(hue: f32, sat: f32, light: f32) -> (u8, u8, u8) {
     )
 }
 
+/// Maakt het demo-venster aan, genereert een regenboogpalet van 32 kleuren
+/// en start een timer die de balken en counter elke 100ms één stap laat schuiven.
 fn main() -> Result<(), slint::PlatformError> {
     let demo = DemoWindow::new()?;
 
-    let colors: Vec<slint::Brush> = (0..38)
+    let n = 32;
+    let colors: Vec<slint::Brush> = (0..n)
         .map(|i| {
-            let hue = (i as f32 / 38.0) * 360.0;
+            let hue = (i as f32 / n as f32) * 360.0;
             let (r, g, b) = hsl_to_rgb(hue, 0.85, 0.55);
             Color::from_rgb_u8(r, g, b).into()
         })
         .collect();
 
     let model: Rc<VecModel<slint::Brush>> = Rc::new(VecModel::from(colors));
-    demo.set_bar_colors(model.into());
-    demo.set_window_title("DEMO Slint".into());
+    demo.set_bar_colors(model.clone().into());
+    demo.set_window_title("Slint & Rust Demo".into());
+    demo.on_exit(|| slint::quit_event_loop().unwrap());
+
+    let weak_demo = demo.as_weak();
+    let timer = Timer::default();
+    timer.start(TimerMode::Repeated, std::time::Duration::from_millis(100), move || {
+        if let Some(demo) = weak_demo.upgrade() {
+            let first = model.remove(0);
+            model.push(first);
+            let c = demo.get_counter() + 1;
+            demo.set_counter(if c >= n { 0 } else { c });
+        }
+    });
+
+    // ─── Voorbeeld: Arduino-achtige loop in een achtergrond-thread ───
+    // Gebruik dit patroon als je zelf een loop nodig hebt (bv. sensoren uitlezen).
+    // De thread draait los van de UI, dus je moet `invoke_from_event_loop`
+    // gebruiken om het venster veilig te updaten.
+    //
+    //     let weak = demo.as_weak();
+    //     thread::spawn(move || {
+    //         let mut i = 0;
+    //         loop {
+    //             i += 1;
+    //             let demo = weak.upgrade().unwrap();
+    //             // `invoke_from_event_loop` stuurt een actie naar de event loop
+    //             slint::invoke_from_event_loop(move || {
+    //                 demo.set_counter(i % 32);
+    //             }).unwrap();
+    //             thread::sleep(Duration::from_millis(100));
+    //         }
+    //     });
 
     demo.run()
 }
diff --git a/ui/demo.slint b/ui/demo.slint
index 12bd9be..125fcfb 100644
--- a/ui/demo.slint
+++ b/ui/demo.slint
@@ -2,21 +2,62 @@ export component DemoWindow inherits Window {
     width: 1920px;
     height: 480px;
 
+    callback exit;
     in property <[brush]> bar-colors;
     in property <string> window-title;
+    in property <int> counter;
 
     VerticalLayout {
         Rectangle {
             height: 60px;
             background: #2d2d2d;
 
-            Text {
-                text: window-title;
-                color: #ffffff;
-                font-size: 28px;
-                font-weight: 700;
-                horizontal-alignment: center;
-                vertical-alignment: center;
+            HorizontalLayout {
+                padding-right: 12px;
+
+                HorizontalLayout {
+                    horizontal-stretch: 1;
+                    alignment: center;
+
+                    Text {
+                        text: window-title+" (";
+                        color: #ffffff;
+                        font-size: 28px;
+                        font-weight: 700;
+                        vertical-alignment: center;
+                    }
+
+                    Text {
+                        text: counter+")";
+                        color: #ffffff;
+                        font-size: 28px;
+                        font-weight: 700;
+                        vertical-alignment: center;
+                    }
+                }
+
+                VerticalLayout {
+                    alignment: center;
+
+                    Rectangle {
+                        width: 70px;
+                        height: 40px;
+                        background: touch-area.has-hover ? #4a4a4a : #3a3a3a;
+                        border-radius: 4px;
+
+                        exit-text := Text {
+                            text: "Exit";
+                            color: touch-area.has-hover ? #000000 : #ffffff;
+                            font-weight: 600;
+                            horizontal-alignment: center;
+                            vertical-alignment: center;
+                        }
+
+                        touch-area := TouchArea {
+                            clicked => { exit(); }
+                        }
+                    }
+                }
             }
         }
 
@@ -25,7 +66,7 @@ export component DemoWindow inherits Window {
             spacing: 0px;
 
             for color in bar-colors: Rectangle {
-                width: 50px;
+                width: 60px;
                 background: color;
             }
         }