As I try to move from goals that are intentionally pointless to those that have some utility, I now want to resume my project of providing a way to build a free high quality servo. Servos are motors that can go to a specific orientation and optionally measure their orientation and/or applied force. Where I'm at, is I want to make a script that generates a printout to make a rotary encoder. Servos usually use potentiometers, which are inaccurate. Rotary encoders can be more precise. Unfortunately, I've misplaced or lost my existing work. But the subgoal is quite simple: A script that generates an wheel of color according to a provided radial function. I think if the darkness of the bands on the wheels increases linearly as a function of angle, the encoder could be calibrated to measure possibly-arbitrary precision via a photocell facing the rotary encoder.