(function() { var World = Matter.World, Bodies = Matter.Bodies, Composites = Matter.Composites; Example.circleStack = function(demo) { var engine = demo.engine, world = engine.world; var stack = Composites.stack(100, 185, 10, 10, 20, 0, function(x, y) { return Bodies.circle(x, y, 20); }); World.add(world, stack); }; })();