Easy print extruder visualizer. The Flexi Rex is my favorite model, so I thought it'd make a fun visualizer. Print flat on the bed. Do a color change to make Rex stand out. There is a very slight indention in the back to help center a magnet. I used an 8mm round magnet. Glue one to the back, then stack up as many as you need to get the right distance from your extruder. I've got 5 magnets total and it works great.

The included GCode is for my i3MK3s with MMU2S and will color swap from extruder 3 to extruder 1.