Napier's Bones
One of the vectors 3d printing opens up is building up from all that has come before. Having a set of bones handy gives us another way to answer math questions and learn something about process, design and production.
These were done up on a Lulzbot Mini using neutral HIPS filament and a quick hand pass with a black sharpie.

https://en.m.wikipedia.org/wiki/Napier%27s_bones