This is a bit of a weird one. It is the very first thing I printed that I designed myself, but it is still one of the most awesome prints I have. Not because it is a complicated design or even hard to print, but because it shows one of the main things 3D printers can do that conventional production methods can't. Namely, printing a working mechanism in one go. The simple fact that the gears are printed around the axles is usually enough to show even the people who care very little about these types of technology why 3D printing is awesome.
Be aware though, even though this part can only be produced using 3D printing, it was not designed to be easilly printable. Support material is required, and removing it from the spaces inbetween the gears and the top and bottom plates will be a pain. Furthermore, you need to use the mechanism a lot before friction will cause the final support wires to break away and allow the gears to move much smoother.
Removing the supports is tricky. There is a thin layer of support material between the gears and the top and bottom plate. I loosened everything up as much as possible using a thin knife and removed any accessible support material, before applying quite a lot of force to the gears in order to break the remaining support material loose. Even when the gears are able to move, not all the support material is accessible and some of it will jam the mechanism a bit. The only way to fix this is to rotate the gears for a very long time, until friction will cause the remaining wires to wear down and allow the mechanism to move smoother.