Spirograph (HTML5 Canvas)

Parameters

Valid ranges: R 20–240, r 5–R, O 0–R. t-step controls speed.

Equation

x = (R + r)·cos(t) − (r + O)·cos(((R + r)/r)·t)
y = (R + r)·sin(t) − (r + O)·sin(((R + r)/r)·t)