Extruder movements on both MK2/S and MK3 can be quite difficult to see. The other three axes are easily visible, and honestly, it can be super mesmerizing to watch. A lot of us always want to know what’s our printer doing. Peter Roodenburg designed the Dutch Windmill motor rotation indicator, and I immediately fell in love with it, so I made a few of my own!

You can read more about these in this Prusaprinters.org article:
https://www.prusaprinters.org/visualize-extruder-motor-movements/

Note that one side of the middle of the visualizer is slightly raised, glue the magnets to the raised side for better spin ;)