diff --git a/main.go b/main.go
index 70af857..0d03195 100644
--- a/main.go
+++ b/main.go
@@ -104,6 +104,12 @@ func physics(particleList *[MAXPOINTS]rl.Vector2, particleCount int, particleLis
 				defer wg.Done()
 
 				// Jede Goroutine arbeitet nur auf Index i → kein Datenkonflikt
+				for l := 0; l < particleCount; l++ {
+					if rl.CheckCollisionCircles(particleList[i], *particleRadius, particleList[l], *particleRadius) {
+						particleSpeed[i] = rl.Vector2Negate(particleSpeed[i])
+					}
+				}
+
 				obstacleReflect(currentPositions[i], &particleSpeed[i], obstacles, particleRadius, obstacleCount)
 
 				newParticleList[i] = rl.Vector2Add(
@@ -150,7 +156,7 @@ func main() {
 	rl.EndDrawing()
 
 	var particleWidth float32 = 300
-	var particleHeight float32 = 200
+	var particleHeight float32 = 300
 	var particleColumnCount int = 20
 	var particleRowCount int = 20
 	var particleCount int = particleRowCount * particleColumnCount