JS1k: The JavaScript code golfing competition

var x=5;
var y=5;
var w=1;
var h=4;

var speed = 1;
var times = 600;
var loop = setInterval(anim, speed);

function anim() {

times--;
if (times === 0) { clearInterval(loop); }

c.beginPath();

if (dx == null) {
var dx=5;
var dy=5;
}

var dx=x++;
c.arc(dx, dy, w, h, 2*Math.PI);

var dy=y++;
c.arc(dx, dy, w, h, 2*Math.PI);

c.fillStyle ='#'+Math.floor(Math.random()*16777215).toString(16);
c.fill();
c.lineWidth = 1;
c.strokeStyle = "#000000";
c.stroke();
}

anim();

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Original source not submitted