By Stephen Hamacek.

A kinetic sculpture inspired by marble machines, marble madness and classic Sesame Street, with a little steampunk flavour :) Created as a Uni assessment piece.

See the animation at https://youtu.be/5LC8PYq_VS0

and more info/discussion at http://blenderartists.org/forum/private.php?do=showpm&pmid=665747

Several amazing procedural wood shaders are by Dale Cieslak, available on Blendswap