[graypegg]

I gave it a try! I tried to get the odd-ball perfectly circular cut and square dimensions, but I'm mostly just eyeballing it. Haven't tried printing it yet, but I have some nice red filament that I think is going to look good!

Here's a screenshot from inside FreeCAD:

https://f.toi.sh/rubygem-screenshot.png

A nice manifold solid:

https://f.toi.sh/rubygem.3mf / https://f.toi.sh/rubygem.stl

A terrifying non-manifold FreeCAD mess: (requires surface WB)

https://f.toi.sh/rubygem.FCStd