Based on a useful everyday tool created by Phei, I decided while creating this customizable object to form a sort of tutorial out of it in the form of 7 progressive scad files, zipped up.

Starting from Phei's included diagram, I first parameterised, then built primitives, moved them, rounded off some corners, and finally added in a fudge factor (tolerance) for the key grab point to the desk based on my experience with my printer.

The result is a tool which can create any sized hook for any desk to hold any item. Simply tweak according to need in the customizer.