Three Pendulum Rotary Harmonograph

A harmonograph is a mechanical device that uses swinging pendulums to draw pictures, believed to be originally invented in 1844 by Scottish mathematician Hugh Blackburn.

This 3-pendulum rotary type of harmonograph gives a wide variety of pleasant results, and is fairly easy to build once you’ve settled on a design and have acquired the appropriate materials and tools.

This is a great project to do with kids and can result in endless experiments creating new types of geometric designs.