Grid positioning based on an increasing index.
var col=5;
var row=4;
var index=0;
addEventListener(Event.ENTER_FRAME,loop);
function loop(e:Event):void {
var xpos=index%col;
var ypos=Math.floor((index/col)%row);
index+=1;
box.x=xpos*box.width;
box.y=ypos*box.height;
}