If you stare at them long enough and hold your mouth right, you can see the figures rotating about both their horizontal and vertical axes. If you keep it up you'll see them change direction and even oscillate. If you keep on going after that, they'll reprogram your brain and make you want to send me money. You might want to check out epilepsy treatments.
For some reason I can't make my brain see the figure in the top row, second from the left rotate about the horizontal axis. If I turn the computer sideways it works but then the horizontal has become vertical.
I made the image using the fantabulous R statistical programming environment, which I heartily commend to anyone interested in data exploration and analysis. Note to the R project guys: Thank you! You guys rock. Anyone interested in seeing the source code can find it here. Anyone wishing to contact me should probably think twice. If you must go through with it, then leave a comment You can also view comments.
Adios!
Um, all this stuff, if you want to use it, just ask because I'll probably let you but just so you know, it's copyrighted (© 2005 Phftt.com) and I retain all rights.