Harmonograph
1840s; invention often attributed to Hugh Blackburn in 1844

Prompt
Transform this image into a Harmonograph drawing, rebuilding its recognizable shapes with fine continuous ink loops, nested oscillations, and gradually contracting spirals. Use repeated crossings to create dense shadow bands and airy open meshes for highlights, all on lightly textured ivory paper. Keep the original subject and composition.
Identify
Fine lines form nested loops, woven meshes, and narrowing spirals. Repeated crossings create dense bands as the drawing gradually contracts.
Principle
Combined pendulum motions move a pen relative to paper, producing curves related to Lissajous figures1. Mechanical damping2 reduces the swings, so successive loops shrink.
Example
Anthony Ashton: Harmonograph: A Visual Guide to the Mathematics of Music, 2003.
Try it out
Suspend a leaking sand cup over a tray, start an elliptical swing, and watch successive loops shrink as the motion fades.
Background
The harmonograph emerged in the nineteenth century, with its invention often attributed to Hugh Blackburn in 1844. Later makers developed several arrangements of pendulums, pens, and moving tables. Some machines move the pen in two directions; others also move the paper. Pendulum lengths help determine the frequency ratio3, which shapes the pattern. Simple ratios can produce orderly, repeating loops. Friction and air resistance gradually drain energy, drawing those loops inward. These machines connected demonstrations of vibration with decorative drawing, making relationships between rhythmic motions visible without photography.
Distinction
A Spirograph uses gears to constrain a tracing point, rather than freely swinging pendulums. Ideal Lissajous figures have constant amplitudes; harmonograph drawings usually show shrinking amplitudes.
Aftermath
The harmonograph shows how simple oscillations can combine into intricate patterns while recording the gradual loss of mechanical energy.
Further examples · 7 images






Question
Why do later loops usually become smaller?
Show possible answer +Hide answer −
Friction and air resistance remove energy from the pendulums. Their swings become smaller, reducing the drawing's reach.