Cube Spinner with Ball-Vertices

- my take on the cube spinner design
- I thought they miss a lot of inertia when only made of plastic, so I added steel balls to all 8 corners
- It got a nice weight to it now!
- 13 mm steel balls are used, and one standard 608 bearing
- you need 2x "Mainbody_half" and 2x "Cap"
- mainbody needs to be glued together after inserting the bearing
- caps need to be glued together
- balls should snap in place
- my printed version was not perfect, as you can see on the pictures, but I changed s