XYZ 20mm Calibration Cube with magnet remix

Thanks to iDig3Dprinting for his fantastic xyz calibration cube that I have printed so many times.
After (felt) hundreds of cubes I got this genious idea:
" modify it so that it has a use after the printer calibration test "

With tinkercad I made a hole in the bottom so that I can put a neodymium magnet inside.

There are two versions:

round:
uses 10mm height, 5mm diameter cylinder magnets

square:
uses 5mm cube magnets

Be aware that the hole is exactly 5mm ... maybe you need t