(function() { var World = Matter.World, Bodies = Matter.Bodies, Composites = Matter.Composites, Common = Matter.Common; Example.avalanche = function(demo) { var engine = demo.engine, world = engine.world; var stack = Composites.stack(20, 20, 20, 5, 0, 0, function(x, y) { return Bodies.circle(x, y, Common.random(10, 20), { friction: 0.00001, restitution: 0.5, density: 0.001 }); }); World.add(world, stack); World.add(world, [ Bodies.rectangle(200, 150, 700, 20, { isStatic: true, angle: Math.PI * 0.06 }), Bodies.rectangle(500, 350, 700, 20, { isStatic: true, angle: -Math.PI * 0.06 }), Bodies.rectangle(340, 580, 700, 20, { isStatic: true, angle: Math.PI * 0.04 }) ]); }; })();