What tool did you use for this?
I do all my work custom in Photoshop. Sorry, there's no ready-to-use app (that I know of) for getting everything the same size and adding nice bevels and drop shadows. I'm a bit obsessive, and so I tweak each tile to maximize its appearance. (This is why I didn't continue the riddle once I understood that it was Mastermind ... my method for making images is too time-consuming for this kind of contest.)