<script>
  function render() {
	  for (var j=0; j<2; j++) {
		  i=i+0.02;
		  var x=w/2+Math.floor(w/2*Math.cos(cos_mul*i));
		  var y=h/2+Math.floor(h/2*Math.sin(sin_mul*i));
		  ctx.moveTo(last_x,last_y);
		  ctx.lineTo(x,y);
		  ctx.stroke();
		  last_x=x;
		  last_y=y;
		  h=h*0.9996;
		  w=w*0.9996;
          }
	  if (h>75 && w>75) {
	    requestAnimationFrame(render,ctx);
	  }
  }

  var c=document.getElementById("canvas2");
  var ctx=c.getContext("2d");
  var h=window.innerHeight*0.9;
  var w=window.innerWidth*0.9;
  document.getElementById("canvas2").width=w;
  document.getElementById("canvas2").height=h;
  var i=2;	
  var cos_mul=5;
  var sin_mul=15;
  var last_x=w/2+Math.floor(w/2*Math.cos(cos_mul*i));
  var last_y=h/2+Math.floor(h/2*Math.sin(sin_mul*i));
  render();

</script>