A new addition to the iTunes Apps Store, Diorama takes the idea of a phone-tilting, marble-in-the-maze-puzzle and gives it the stereoscopic treatment. The maze becomes a three-dimensional room with several stories and a system of stairs, ramps, tunnels, and cliff-hanging pathways for you to try to balance a tiny ball through. It's an excellent illusion, one that makes it look like your iPhone or iPod Touch's screen has given way to an actual space in another dimension.

You can play with our without a pair of 3D glasses it works just as well in both modes, although you'll get more head-spinning depth with the glasses on. The developers are willing to send out a pair of glasses to users in the US who send in a self-addressed envelope, but any red-and-blue glasses will do. There are nine puzzles included. The first one is very tricky, but once you get past it the difficulty does let up. Search for "Diorama" in the Apps Store and you'll find it for 99 cents, which it more than lives up to.