Animated Engines

I want to build one of these.

[SGW]

He says they're animated .gif files. I think you ought to be able to save the .gif, then open it with a program that can edit animated .gifs and jigger the timing.

[aostling]

I wish there was a way to slow the animation speed. Any suggestions?

[Mad Scientist]

Some of these designs will make your head spin.

http://www.keveney.com/Engines.html