diff --git a/apps/pongclock/app.js b/apps/pongclock/app.js
index e6f8355ea..932c1f3d7 100644
--- a/apps/pongclock/app.js
+++ b/apps/pongclock/app.js
@@ -28,7 +28,7 @@ class Ball {
     }
 		if (test) {
 			this.velX = -this.velX;
-      this.valY = (3.5 + 2 * Math.random()) * this.valY / Math.abs(this.valY);      
+      this.velY = (3.5 + 2 * Math.random()) * this.velY / Math.abs(this.velY);
 
       if (isLeft) {
 				right.follow = this;