This is a video of a clock that I created. The numbers for the clock are on wood rectangles that are mounted on steel roller chain. With every minute the right side chain is moved into a new position. All of the chains are powered by a gear motor.
This clock is currently for sale at:
http://www.ebay.com/itm/232034222432?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649