This is a super tiny print to test the thermal contraction of your filament, as well as the accuracy of your print size. I made this to dial in my scaling for prints that require specific tolerances, such as fitting bearings on TUSH spool holder.

Each step is 5mm wide, so the entire print is 25mm horizontal. Each step on the vertical axis is 1mm, stepping up to 5mm. This allows you to check contraction on both planes with a set of metric calipers.