Nice effect. Reminds me of lissajous from my Basic days...

I didn't know that particular program, in fact I've managed to (almost) always stay away from Basic but of course I'm familiar with Lissajous figures, which I also considered, although those would have required either ANSI sequences (and then are nice to be seen while being drawn - I wanted something to paste into email instead) or mangling with a buffer, whereas my program is both much simpler and gives me what I wanted, that is a potentially very long output. Lissajous figures by contrast are always constrained in a rectangle (if you don't consider rescaling, a square).