Inverse Turners Cube

A turners cube is a great way to test your skills on a lathe, mill or even a drill press if you've got a few screws loose upstairs. This one will test your skills on a 3D printer. This is a complete opposite of the classic turners cube with the rounds on the outside and the squares on the inside. 100mm OD.

As always, super bonus points if you print this out and post the pictures.

Twisted version for those who are feeling especially brave.