David Jones has built a number of ingenious “fake” perpetual motion machines for museums and trade shows. These are beautifully made of bicycle wheels, sewing machine parts, plumbing hardware and other embellishments. They are displayed in glass or clear plastic cases with no obvious means for energy input. Observed by visitors daily, they slowly turn, day after day, without diminution of speed, over periods of a year or more, seemingly in defiance of the laws of physics. Sometimes a nice prize is offered to anyone who can puzzle out the precise secret of their operation. Jones once said that an analysis of the entries showed that many engineers thought that he really had discovered the secret of perpetual motion, while many physicists proposed methods of deception that couldn’t possibly work.