This is a fully functioning Rubik's cube that's printed in one piece (no assembly required). I extruded the letters G, E and B through its faces so that when the cube is solved, you can see through the cube on its corner pieces. It's a riff of the cover to GÃ¶del, Escher, Bach: An Eternal Golden Braid.
I designed this project in OpenSCAD and made the letter extrusions independent of the cube itself. I've also uploaded the .scad code so you can design your own extrusions, or just print the cube. Enjoy :)