Different sized tiles auto fill grid ??? Brain Hurts.

[0knowledge]

I have a situation where I need to fill a grid with tiles that will be of different sizes, but all multiples of a base unit size. Can anyone point me to an example of this already implemented, or some actionscript examples?

Here is a more detailed explanation of what I'm doing.
You would have a grid that is of n units wide by n units tall. Then tiles that are also n units wide by n units tall. I want to then give a function a random number of tiles to place into the grid, without having any tiles overlap. It will then place a tile at a random position on the grid, but not in any grid cells that have already been covered by a tile.

I have been searching google, but I can't seem to find anything that applies.

Thanks for any help.

[691175002]

If you need a specified number of tiles it depends on the kind of look you want.

Two simple thoughts that come to mind would be filling with 1x1 tiles and then merging them until you get the right number of tiles.
Another would be to fill with a small number of big tiles and then divide them randomly until you get the right number.