These print in place bearings take 24 minutes and can be printed to understand the engineering and how ball bearings work or they can be printed for a fidget toy!
If you guys want just the STL file, you can print for free here:https://makerworld.com/en/models/17245#profileId-33465
Print In Place Ball Bearings by hitcha (Amelia Hitchcock) is licensed under CC BY-NC-ND 4.0