Harmonogram. This unique pattern was created using a device called a two-pendulum harmonograph. This piece of equipment consists of two pendulums, each suspended from a universal joint, with one pendulum hanging lower than the other. In this case, the higher pendulum had a camera attached to its base, while the lower pendulum had an LED that pointed up at the camera when at rest. In a blacked-out area, both pendulums were set swinging. The camera shutter was opened before the LED was switched on. After about a minute, the LED was switched off and the camera shutter closed. Harmonographs were pioneered by the French physicist, Jules Antoine Lissajous in 1857.