Slightly modified the OpenSCAD file as I wasn't happy with the way the gear teeth intersected the cube - the 'horns' on the large gears in the original were very fragile and didn't look great.This involved changing the gear teeth counts (from 18/9 to 18/12) and adding a 'rotation_tweak' parameter to the code that lets you adjust the rotation of the gears, so adding 5 degrees (half a tooth) moved the 'horns' from the large gear to the small ones.As I don't have MatLab, I rewrote the gearopt.m script in perl, it's below as gearopt.plSlice in skeinforge or other and print on your 3D printer of choice.To play with the OpenSCAD model, you need these additional bits:Parametric Involute Bevel and Spur Gears by GregFrost http://www.thingiverse.com/thing:3575Weighted Storage Cube (from Portal) by cyrozap (don't fix the typo in the filename!) http://www.thingiverse.com/thing:1614