Any Metroid fans around? Here is my take on Samus' emblem that you can use as an extruder indicator.
Print in PETG or PLA with 100% infill and glue 2x 8x3mm magnets to the back of the print. For multiple colors use print stops where needed (in .3mf already added).
Note:
Initially I printed the emblem with a 0.4mm nozzle but I was't satisfied with the quality. The problem is, that because of the sharp angles there were a lot of holes on the surface. So I reprinted it with a 0.25mm nozzle and now it looks great. That's the way to go to achieve the best outcome with this model.
With a litte tweaking and tuning in the setting it may be possible to also get a good result with a 0.4mm nozzle.
Have fun and happy printing.
The author marked this model as their own original creation.