<div id="mydiv" style="height:320px;width:320px;"> </div>

<div style="position:absolute;top:10px;left:10px;width:1px;height:1px;"></div>

<script>
sx = 200;
sy = 300;
amp = 100;
i = -100;
j = 0;
function addpoint(x,y) {
document.write('<div style="position:absolute;width:1px;height:1px;left:'+(sx+x)+'px;top:'+(sy+y)+'px;margin:0px;padding:0px">.</div>');
}
while(i<100) {
addpoint(i, amp*Math.cos(j)*Math.sin(i/10));
j+=0.05;
i++;
}
sx = 410;
function addp(x,y) {
document.write('<div style="position:absolute;width:1px;background-color:#000;height:1px;left:'+(sx+x)+'px;top:'+(sy+y)+'px;margin:0px;padding:0px"></div>');
}
i = -100;
j = 0;
while(i<100) {
addp(i, amp*Math.cos(j)*Math.sin(i/10));
j+=0.01;
i++;
}
</script>