Things Made of Cardboard very cleverly built a harmonograph out of their favorite medium. This kinetic structure employs pendulums and a swinging board to create Lissajous curves of varying sizes with an attached pen.
The harmonograph is so far the best device I have ever made out of cardboard. It uses pendulums to control the movement of the pen relative to the drawing surface and creates Lissajous figures. Although it looks simple, it took a long time to work so well.
submitted via Laughing Squid Tips