Ok, did anyone else ever read Arthur C. Clarke's sci-fi novel, Rendezvous with Rama? The connection here is a little thin, but I had a distinctive flashback when I saw it. In Clarke's story, astronauts land on a visiting spaceship, initially thought to be dead, but which later turned out to be the home of all sorts of robots.
Everything on Rama reflects a theme of "three", including one type of robot that Clarke describes in great detail. This spider-robot is said to look like a three-legged daddy longlegs, and the way it moved sounded pretty far-fetched, at least until I saw this robot from Virginia Tech. I'm sure this won't turn out to be the most practical form of locomotion, but it's a wonderful example of thinking outside the box. (read more about it on Engadget)