3D printed planetary gear boxes

Clever build as the author designed them to be stackable, so you can go to 1:4, to 1:16, to 1:64. The STL files are not hosted on a standard 3D site, which is a bit odd.

https://www.hackster.io/news/3d-printable-stackable-planetary-gearbox-provides-unlimited-reduction-7d63d27b36ce