sin cos rot back

HTML

<div>*</div>

CSS

div {
    position: absolute;
    top: 50%;
    left: 50%;
}

JavaScript

$(function() {
    var fps = 100;
    var a = 0;

    draw = function() {
        a += 0.001;
        var x = ((Math.cos(a) + 1) / 2) * 90;
        var y = ((Math.sin(a) + 1) / 2) * 90;
        $("div").css("left", x + "%");
        $("div").css("top", y + "%");
    }

    update_frame = function(fps) {
        draw();
        setTimeout(function() {
            update_frame(fps)
        }, (1000. / fps));
    }
    update_frame(fps);
});