General-purpose NEMA 14 stepper motor casing

This is a general-purpose casing for NEMA14-size stepper motors.

I tried to make the casing relatively insensitive to heat by avoiding unnecessary surface contact of the casing and the stepper. The purpose of this design approach is to enable one using PLA only for printing without having noteworthy deformations during operation due to the high heat generated by the stepper.

To create a complete casing you need to print 2 covers, 1 belt, and 4 corners.

Additionally, I added a simple oct