Box with snap-on lid

Parametric box, careful with the settings - you can make some nonsense shapes.

The default settings make a tight snap-fit lid. I printed a second one of these with pre-made holes as an electronics project box, you can customize the holes if you edit the .scad file.

The customizer seems to be suffering from this issue:
https://www.thingiverse.com/groups/thingiverse/forums/site-issues-and-feedback/topic:26898
at the moment, hopefully that will get fixed on the server - there's nothing weird in the .scad file. Meanwhille, if you want to customize the thing, I strongly suggest getting OpenSCAD and just playing with the .scad file directly.