Results
Two-pendulum results
To simplify things, you can lock down the rotary pendulum by unclipping that weight so it rests on the floor and prevents the paper platform from swinging at all. Attach the other weights at their lowest position to start, since a slower pen speed tends to give smoother lines. If the two other pendulums swing in unison at the same frequency you will get simple patterns of circles, ellipses, or lines. If their frequencies are slightly different, the pattern will slowly change from circles to lines and back again as it decays, which will give eye-like designs. When the frequencies are very different, you may get chaotic looking results. However, if you find a position that is near a "harmonic" ratio of frequencies such as 3:2 or 4:3 you can get pleasant Lissajous figures, figure eights, or fish-like shapes.