1000 circles moving and bouncing of edges

1000 circles bouncing of the edge in random direction. I don't think this works well on slow machines. Inspired by ease()-y as Math.PI by @alignedleft

forked from maartenzam's block: 1000 circles moving and bouncing of edges

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
    #vis { width: 100%; height: 100%; }
  </style>
</head>

<body>
	<div id="vis">
	</div>
	
  <script>
    var width = document.getElementById("vis").clientWidth;

d3.select(this)
			.transition()
			.duration(10000 + 20000*Math.random())
			.ease("linear")
			.attr("cy", newy)
			.attr("cx", newx)
			.each("end", move)
	}
    
	var i;
    for (i = 1; i < 1000; i ++) {
    	var circle = svg.append("circle")
      	.attr("r", 2 + Math.random()*20)
      	.style("fill", "#9a0b16")
		.style("opacity", 0.7);
	circle.transition()
		.delay(20*i)
		.duration(10)
		.attr("cy", 0)
		.attr("cx", width*Math.random())
		.each("end", move);
    };
    
  </script>
</body>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js