XY Calibration - tiny

Quick XY calibration test.

Update 4. replaced with a better OpenSCAD file.
Update 3. added 100 x 100 with better adhesion if you don't have OpenSCAD, could be the best file to use.
Update 2. added line width in OpenSCAD file, for better adhesion
Update 1. fixed a dimension problem.

You need to measure the distance between either
a) inside of small rectangle to inside of big rectangle
or
b) outside of small rectangle to outside of big rectangle.
on both X and Y axis.
See the image posted.

Let the object on print surface when you measure it.

Included 20 x 20, 100 x 100, 150 x 150, 200 x 200 and OpenSCAD file to produce a particular size for test, if needed

If you have problem with adhesion, you can use whatever way to have a good adhesion (even brim) and scale the object only on Z axis then measure the distances on upper layers, some helper image included as well.
As of update 2 and 3, you can increase line width (in OpenSCAD) for better adhesion, preview in