===================================================================
--- original.js
+++ change.js
@@ -94,12 +94,11 @@
 	tree.y = 2732;
 	trees.push(tree);
 	game.addChild(tree);
 }
-var grass = new Grass();
+var grass = game.addChild(new Grass());
 grass.x = 0;
 grass.y = 2732;
-game.addChild(grass);
 // Handle touch events to make the bird fly upwards
 game.down = function (x, y, obj) {
 	bird.speed = -10; // Move bird upwards
 };