Trefoil Extruder Movement Visualizer

This is a design based on the Extruder rotation vizualizer (https://www.thingiverse.com/thing:2759852) but not a "remix".

UPDATE 12-2-2019: Added a version meant to fit on the x-axis motor shaft.

UPDATE 6-1-2018: I changed the inner diameter to 8 mm. Mounting is accomplished with 2 magnets stacked to reach the extruder motor shaft.

The inner diameter of the Trefoil is 8 mm which should fit the smaller neodymium magnets available from Home Depot and Lowe's without the need for glu