diff --git a/src/main.rs b/src/main.rs
index f1134d3..c4b1546 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -93,16 +93,6 @@ fn main() {
 	const R_SKY: f32 = R_SCALE * N_TEETH_SKY as f32;
 
 	const FPS: f32 = 60.0;
-	const V_SUN: f32 = 2.0;
-	const V_SKY: f32 = -1.0;
-
-	const V_SAT: f32 = (V_SKY - V_SUN) / 2.0;
-	const V_ORBIT: f32 = (V_SUN + V_SKY) / 2.0;
-
-	const W_SUN: f32 = V_SUN / N_TEETH_SUN as f32;
-	const W_SKY: f32 = V_SKY / N_TEETH_SKY as f32;
-	const W_SAT: f32 = V_SAT / N_TEETH_SAT as f32;
-	const W_ORBIT: f32 = V_ORBIT / (N_TEETH_SUN + N_TEETH_SAT) as f32;
 
 	with_2d_graphics(|| {
 		let sun = gear_shape(N_TEETH_SUN);
@@ -110,21 +100,24 @@ fn main() {
 		let crown = gear_shape_outer(N_TEETH_SKY);
 
 		let (canvas, mut events) = create_drawing_window_with_events("Canvas window");
-		let mut frame = 0;
+		let mut t = 0.0f32;
+		let mut angle_sun = 1.0 / N_TEETH_SUN as f32 * PI;
+		let mut angle_sky = 0.0;
+		let mut angle_sat = 0.0;
+		let mut angle_orbit = 0.0;
 		'main: loop {
 			while let Poll::Ready(event) =
 				events.poll_next_unpin(&mut Context::from_waker(Waker::noop()))
 			{
 				let Some(_event) = event else { break 'main };
 			}
-			let t = frame as f32 / FPS;
 			canvas.draw(|gc| {
 				gc.clear_canvas(Rgba(0.1, 0.1, 0.1, 1.0));
 
 				gc.canvas_height(100.0);
 				gc.line_width(0.25);
 
-				let m = Mat2::from_angle(t * W_SUN + 1.0 / N_TEETH_SUN as f32 * PI);
+				let m = Mat2::from_angle(angle_sun);
 				gc.new_path();
 				for pt in &sun {
 					let pt = R_SUN * m * pt;
@@ -134,9 +127,9 @@ fn main() {
 				gc.stroke_color(Rgba(0.8, 0.7, 0.1, 1.0));
 				gc.stroke();
 
-				let mr = Mat2::from_angle(t * W_SAT);
+				let mr = Mat2::from_angle(angle_sat);
 				for k in 0..N_SAT {
-					let mo = Mat2::from_angle(t * W_ORBIT + k as f32 / N_SAT as f32 * 2. * PI);
+					let mo = Mat2::from_angle(angle_orbit + k as f32 / N_SAT as f32 * 2. * PI);
 					gc.new_path();
 					for pt in &sat {
 						let pt = mo * vec2(OFF_SAT, 0.) + R_SAT * mr * pt;
@@ -147,7 +140,7 @@ fn main() {
 					gc.stroke();
 				}
 
-				let m = Mat2::from_angle(t * W_SKY);
+				let m = Mat2::from_angle(angle_sky);
 				gc.new_path();
 				for pt in &crown {
 					let pt = R_SKY * m * pt;
@@ -157,7 +150,18 @@ fn main() {
 				gc.stroke_color(Rgba(0.1, 0.4, 0.8, 1.0));
 				gc.stroke();
 			});
-			frame += 1;
+
+			let v_sun: f32 = 1.0 + 2.0 * (0.007 * t).sin();
+			let v_sky: f32 = 1.0 - 2.0 * (0.003 * t).cos();
+			let v_sat: f32 = (v_sky - v_sun) / 2.0;
+			let v_orbit: f32 = (v_sun + v_sky) / 2.0;
+
+			let dt = 1.0 / FPS;
+			t += dt;
+			angle_sun += dt * v_sun / N_TEETH_SUN as f32;
+			angle_sky += dt * v_sky / N_TEETH_SKY as f32;
+			angle_sat += dt * v_sat / N_TEETH_SAT as f32;
+			angle_orbit += dt * v_orbit / (N_TEETH_SUN + N_TEETH_SAT) as f32;
 		}
 	});
 }