A piece I printed turned out to be of a different size than it should be. I couldn't figure out what was going on so I created this test piece set to check what's working ok and what is not.

In perfect world, all six pieces should be identical, except for the sequence markers. In addition, the diagonal pieces (nr. 5 and 6) should be straight. (All pieces should of course be straight but for the others it's seldom a problem.)

As can be seen, my pieces are pretty far from identical. Looks like in my X axis, the relationship between stepper rotation and print head movement is nowhere near linear... edit: the steel reinforcements in the X belt were completely busted