Circle Tracing

I am trying to create a circle with different images.

var j = 0;
var degree30 = Math.PI/6;
var r_angle = 0;

function rotate(idy){
var x = parseInt(Math.cos(r_angle)*100);
var y = parseInt(Math.sin(r_angle)*100);

document.getElementById(idy).style.left = (x + 300);
document.getElementById(idy).style.top = (y + 186);
j++;
(r_angle < degree30 * 11) ? r_angle = degree30 * j : r_angle = 0;

( j < 12) ? setTimeout("rotate('reduit'+ j)", 400) : stop();
}