A simple calibration ruler and numbers font for OpenSCAD.
A simple mono-spaced number font designed for 10x10mm per digit.
To use the font put numbers.scad in the same dir as your scad file, import it with
To calibrate your printer print out the ruler and check that it is 100x15x1mm. If it is it may be slightly more useful than a cube. It's not very useful for Z calibration of course.