For Christmas, my sweetheart bought me Ed Pegg Jr.’s cool Chaos Tiles. Here is a snapshot of mine in action.
Notice how you can go for order or chaos, depending on your taste. The whole thing is very appealing. I happily endorse this product.
I was inspired to look for some more sources on the web. Here’s a pretty good Java applet to play with the Penrose tiles in the shapes that I first read about (there are several kinds of Penrose tiles, you’ll be glad to know). This implementation is by Shuxiang Zeng.