It's a spirograph where the wheel ratio keeps changing between ratio1 and ratio2 (if they're both the same, you get a "regular" spirograph). Frequency is how many times it does it during a full round. "Wheels" shows a simulation of the spirograph's wheels, "[re]Draw" clears and draws. If you move the mouse to the bottom while in "draw" mode, controls disappear.
Keyboard shortcuts: [Unlike the sliders, keyboard lets you change frequency and ratios in 0.1 steps. Otherwise - the shapes you get are a bit boring :)] 1/2: change frequency, q/w: ratio1, a/s: ratio2, z/x: color, r: redraw.
