Harmonagraph

The images below were created with a harmonagraph that I built. A harmonagraph is a kinetic art machine invented in 1844, by the Scottish mathematician Hugh Blackburn. My harmonagraph uses 3 pendulums- one double axis pendulum moves the paper and two single axis pendulums move the pen. 

Harmonagraphs were created to study wave motion and harmonic vibration. One thing I find particularly interesting about the harmonagraph is that for the drawings to come out looking good, the pendulum frequencies have to match the sound wave frequencies of notes that sound good together (musical 3rds, 5ths, octaves, etc.) So these drawings can be seen as visual representations of musical harmony.