XY Stepper motor calibaration grid

This simple test print a grid 5x5 or 10x10
This is useful for understanding if the belt is ok, in my own printer after the test i had to change the belt, because several lines were mis-printed, some line are exactly at 10mm, some other are at 9.6mm

To do the test print directly th gcode files, i put an stl file only because otherwise I can't publish