Harmonigraph revisited

A harmonigraph is still on my To-Build list (have you seen one yet?), so I’m still making do with a simulation.  I tweaked my first attempt to make it even awesomer. 

Now the color changes over time, and I narrowed down the possible periods for the pendulums, and it’s not so boring to watch because it’s super fast.  Try it out - click two places to get a new image (try two close to center).

This simulation uses the parametric equations
x = sin (A t) + sin (B t)
y = cos (A t) + sin (C t)
with the period of each component limited to a value between 2 and 2.5.