diff --git a/src/step.wgsl b/src/step.wgsl
index f4ba49a..8650493 100644
--- a/src/step.wgsl
+++ b/src/step.wgsl
@@ -36,9 +36,7 @@ fn on_fragment(in: Varying) -> @location(0) vec4u {
 	n -= state;
 
 	let z = daynight(state.z, n.z);
-	let px = life(state.x, n.x);
-	let nx = 1u - life(1u - state.x, 8u - n.x);
-	let x = z * px + (1u - z) * nx;
+	let x = life(state.x, n.x + n.z);
 	return vec4(x, 0, z, 0u);
 }