I made this test because i noticed that the height of my prints isn't exact anymore.
I first printed a common testcube. To find out at which point the issue occurs i made this. I noticed that the first step of the pyramid is a little lower than the others. By looking at the leadscrew of the z-axis i noticed that it is harder to turn the screw at this height. So my test helped me because it indicated where the inconsistency occurs.
This test exists also as a Square. Check out the thing 3268324
plasty mladec PLA