Prusa Compact MMU2 Spool Holder

A compact spool holder for the Prusa MMU2 & MMU2S which automatically collects the unloaded filament in a secondary spool to prevent tangles.

See video of operation: https://youtu.be/nxi6TSk1YOY

This is based on [kommisar's fantastic MMU2 Spool Holder](https://www.thingiverse.com/thing:3228827) and can be printed on a single build plate. This version also has the spool holder number integrated as a multi-color print.

### Additional parts
* 5 x 608 bearings
* (optional) M3 x 10mm screw