Customizable FreeCAD clip/snap-fit case

I used [0707070s snap fit boxes](https://www.thingiverse.com/thing:2866563) for past projects. Sadly OpenSCAD isn't really what I'm usually using and editing STLs in FreeCAD is kind of buggy, so customizing them wasn't that much fun. To make my life somewhat easier I modeled a similar design as a customizable FreeCAD box.

Inside the FreeCAD file you'll find a spreadsheet named variables. Open it and change width, length and height according to your needs. The resulting model should update aut