Looks great fun :-) I've been involved with Meccano for years and there's a popular family of models that are sort of perpetual versions of this sort of thing,

Looks great fun :-) I've been involved with Meccano for years and there's a popular family of models that are sort of perpetual versions of this sort of thing, sending balls on endless loops. The best ones are a bit functionally dense to really appreciate except in person, but here's one I saw a few years ago: http://www.youtube.com/watch?v=jf25bYSjD9M http://www.youtube.com/watch?v=jf25bYSjD9M