diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..1ecbea8
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,38 @@
+#[derive(Clone, druid::Data)]
+pub struct Path {
+    pub kurbo_path: druid::kurbo::BezPath,
+}
+
+#[derive(Clone, druid::Data)]
+pub enum CanvasElement {
+    Freehand {
+        path: Path,
+        thickness: f64,
+    }
+}
+
+impl CanvasElement {
+    pub fn bounding_box(&self) -> druid::Rect {
+        match self {
+            CanvasElement::Freehand{ path, thickness } => {
+                use druid::kurbo::Shape;
+                path.kurbo_path.bounding_box().inflate(*thickness, *thickness)
+            }
+        }
+    }
+    pub fn draw(&self, ctx: &mut druid::PaintCtx) {
+        match self {
+            CanvasElement::Freehand{ path, thickness } => {
+                use druid::RenderContext;
+                let stroke_color = druid::Color::rgb8(0, 128, 0);
+                ctx.stroke(&path.kurbo_path, &stroke_color, *thickness);
+            }
+        }
+    }
+
+    pub fn get_path_mut(&mut self) -> Option<&mut Path> {
+        match self {
+            CanvasElement::Freehand{ path, .. } => Some(path),
+        }
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 0e87c24..8fc3d97 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -19,50 +19,6 @@ use druid::kurbo::BezPath;
 use druid::widget::prelude::*;
 use druid::{AppLauncher, Color, Data, Event, LocalizedString, WindowDesc};
 
-mod stiletto {
-    use druid::widget::prelude::*;
-
-    #[derive(Clone, druid::Data)]
-    pub struct Path {
-        pub kurbo_path: druid::kurbo::BezPath,
-    }
-
-    #[derive(Clone, druid::Data)]
-    pub enum CanvasElement {
-        Freehand {
-            path: Path,
-            thickness: f64
-        }
-    }
-
-    impl CanvasElement {
-        pub fn bounding_box(&self) -> druid::Rect {
-            match self {
-                CanvasElement::Freehand{ path, thickness } => {
-                    use druid::kurbo::Shape;
-                    path.kurbo_path.bounding_box().inflate(*thickness, *thickness)
-                }
-            }
-        }
-        pub fn draw(&self, ctx: &mut druid::PaintCtx) {
-            match self {
-                CanvasElement::Freehand{ path, thickness } => {
-                    let stroke_color = druid::Color::rgb8(0, 128, 0);
-                    ctx.stroke(&path.kurbo_path, &stroke_color, *thickness);
-                }
-            }
-        }
-
-        pub fn get_path_mut(&mut self) -> Option<&mut Path> {
-            match self {
-                CanvasElement::Freehand{ path, .. } => Some(path),
-            }
-        }
-    }
-}
-
-struct CanvasWidget;
-
 use stiletto::CanvasElement;
 
 #[derive(Clone, Data)]
@@ -77,6 +33,8 @@ impl CanvasData {
     }
 }
 
+struct CanvasWidget;
+
 impl Widget<CanvasData> for CanvasWidget {
     fn event(&mut self, _ctx: &mut EventCtx, event: &Event, data: &mut CanvasData, _env: &Env) {
         match event {
@@ -177,8 +135,25 @@ impl Widget<CanvasData> for CanvasWidget {
     }
 }
 
+fn build_ui() -> impl Widget<CanvasData> {
+    use druid::widget::{Align, Button, Flex, CrossAxisAlignment, SizedBox};
+    let toolbar = Flex::row()
+        .cross_axis_alignment(CrossAxisAlignment::Center)
+        .with_spacer(30.0)
+        .with_child(
+            Button::new("Undo"))
+        .with_child(
+            Button::new("Redo"));
+
+    Flex::column()
+        .cross_axis_alignment(CrossAxisAlignment::Center)
+        .must_fill_main_axis(true)
+        .with_child(SizedBox::new(Align::left(toolbar)).height(50.0))
+        .with_flex_child(CanvasWidget {}, 1.0)
+}
+
 pub fn main() {
-    let window = WindowDesc::new(|| CanvasWidget {})
+    let window = WindowDesc::new(build_ui)
         .window_size((1024.0, 1400.0))
         .title(
             LocalizedString::new("custom-widget-demo-window-title").with_placeholder("Stiletto"),