Mechanisms are fascinating, and extremely important to our world, from power stations to electric toothbrushes. You may want to build a complicated machine or just make some gears turn, or anything in between. Allowing you to learn about mechanisms as you play.
It is based around magnetic hubs which hold gears and pulleys in between them.
A great way to teach how muscles and tendons work as you can't push a tendon, so you have to find another one to pull, as well as the anatomy of the hand and arm.
This works great as a supervised demonstration, but it could be built as an exhibit for a museum.
This version was built a long time ago in a student living room, we could do a much neater job today, but it is such an effective demonstration we wanted to list it.