ActionScript 3.0 :: Create A Random Square Every Frame Of An Animation?

I'm trying to create a random square every frame of an animation.The trick is, this square isn't allowed to overlap any other squares currently on the stage.I've got code that works all fine and dandy but... after a few hundered squares it slows right down.There must be a way to optimise this, at the moment I've go a while loop telling checking the random squares position against all the others already on the page. If it doesn't intersect, it draws it and carries onto the next frame.After a few thousand attempts, it makes the max and minimum size the square can be smaller, to give it a better chance of fitting in the gaps.And then continues getting smaller after multiple thousand more attempts.Here's my code...

var squares:Sprite = new Sprite;
addChild(squares);
var squares_arry:Array = new Array;[code]....