
Way back when home 3D printing was young(er), Adrian and crew did some forethought into drill holes that’d need to be printed horizontal while still obeying the 45-degree angle rule. (At the time, the many experiments in bending or breaking this rule that would follow were unattainable, as RepRaps, MakerBots, and their kin had not been implemented yet.) The solution: make the hole into a teardrop shape, so that plastic being built up on either side would not droop and clog the hole.
This technique worked, but it was later found that for small holes you can (usually) get away with completely cylindrical holes if you’re willing to run a bolt through them a few times first.
There also was a (somewhat ill-advised) tradition of building a shot glass as one’s first print and drinking to the new machine’s health. Combining these two bits of living 3D printing history, we have Ron Aldrich’s very attractive teardrop shot glass, which he offers with a tip to use food grade urethane to make the glass usable.