One-Motor Synchro Drive

Seeing funny_fish's 1 Motor Synchro Drive on NXTLog, young humanoid wanted to build one.  However, while funny_fish used a floating worm gear, young humanoid wanted to use a differential unit.  The resulting 3-wheel synchro drive worked quite well, although it was a bit slow. 

Please don't blame me for the terrible picture.  It's young humanoid's fault.