Debossed XYZ Cube

3 blank sides, 3 debossed sides marking X, Y, and Z axis for axis calibration. Now there is no confusion about which axis you are measuring.

I find the guide linked below handy for calibrating, so I won't go step by step here.

https://all3dp.com/2/how-to-calibrate-a-3d-printer-simply-explained/