Interesting compact high ratio transmission design

[s_forbes]

Those of you into Rubik's Cubes may know about this guy; Oskar is a puzzle designer that makes crazy cool stuff on Youtube. Here's his channel.

A few weeks ago he posted this simple three piece transmission, with a reduction of 27:1. It works on a similar concept to harmonic gearboxes. This seems like a design that might work for some mechanisms on the robots we build, particularly for something that needs a very large reduction and doesn't see a lot of torque. A similar design could probably be printed and interfaced to a motor quite easily, giving a cheap and quick gearbox for those teams with 3d printers.

If that's not enough, here's a variation on that concept that goes up to 11,373,076:1.