Biohazard Extruder Visualizer

Based on the idea of many existing visualizers, see [Prusa's article](https://www.prusaprinters.org/visualize-extruder-motor-movements/) for more information, but this one is based on the Biohazard symbol. See it in action on [Youtube](https://www.youtube.com/watch?v=k7Vee8Zn6uc). This is designed to work with a Prusa i3 MK3 but should work with other NEMA steppers like it has.

I planned to print the connecting rim and middle circle on the back in black instead to make them more invisible but haven't gotten a good opportunity yet. The two I've made were both printed with Prusa Orange PETG, 0.2 mm layer height.

The size as-is is a bit on the large side, I recommend printing at 70% instead, see photos for size comparison.