It`s a cube that inside have une sphere, it´s very simply but is funny... enjoy with this cube.

I Draw in AutoCAD, 3D modeling easy

P.s: for a good results work with low speed 10 or 20 mm/s, and the height filament 0.1 or 0.15mm

the dimensions is small, if you want can duplicate tham, don´t have problems with the piece.