Earth in the palm of your hands. Mess with Earth till it looks exactly the same as before. :-) Based on Emmetts screwless Heartgear: http://www.thingiverse.com/thing:12208 and the textured earth by bld: http://www.thingiverse.com/thing:17336 Takes one revolution till it is back to normal. Size is 140mm in diameter. Good luck with the assembly, it's quite tricky. ;-)If you want to build one, it's best if you take the earthgears.stl and split in your slicer to arrange it manually. Do the same if you want to have individual parts. You need eight pinpegs (the small part in EarthgearsCenterPinpeg.stl) and one of the center part (the big one in the same file). If you want to do one with the openscad file, place the heart.stl in the same folder where your Earthgears.scad is. Be aware of a very long rendering time. It took several hours on my machine (which is not the fastest one ;-)) because the rendering detail is apparently ridiculous.