I've always wanted to build a laser spirograph with more than two motors to see what would happen, but since I got my Spencer projector I wondered if I could just simulate a 4-motor spirograph in software and display the result. So, I'm working on the alpha software pictured below:
Right now you can control the RPM and "deflection radius" of each motor. Motors are reversible, just dial in negative RPM. If you set the radius and speed of motors 3 and 4 to zero, you have your classic two-motor spirograph. The third motor adds some interest. The fourth motor really makes a mess.
You can dump a single frame to a text file suitable for import in to LaserBoy for processing. Right now the color is hard coded to blue, but you can change that in the text file or in LB.
You can choose keyframes and the software will animate between them to a text file suitable for import into LaserBoy. I use LaserBoy to output ILDA files, but eventually I may just write them directly.
Here is a video (maybe too long) of some sample output. Skip from 5:00 to about 6:10 to see some better patterns.
http://youtu.be/l-eaKHE4fmo
Version 3 (2014-08-05):