This work consists of two model railway lines, both the same length. One describes a circle and the other a straight line. They are presented on very simple wooden structures which are of table height and are just strong enough to support them.

On each railway is a vehicle made of an electric motor balanced by a small lead weight on a chassis with four wheels. At one end of each vehicle is a bright light. They travel at the same speed on the two lines. The one on the straight line travels up and down endlessly, and the one on the circle travels round and round and round.

(2004)