This is a truncated corner compatible with the old Rubik's Cube. I figured since this is the puzzle that many modders make as their first mod, I would make it the first puzzle that I design. Next up, Octagonal Barrel and Fisher Cube! 3D Print TruncatedCorner.stl x8, and replace the corners of your standard Rubik's Cube with these, OR download a Rubik's Cube that is fully printable and compatible with these pieces HERE- https://www.myminifactory.com/object/3d-printable-rubik-s-cube-9734 or print the Rubik's Magic Cube from NudelP, which you can find here- http://www.thingiverse.com/thing:2244. Thanks to AnthonyMouse for the Pictures of these pieces on a Sudoku Cube! I will be stickering mine soon!