This may not be a new invention, but I've never seen it before. It's a cube trapped inside a sphere (ball), and prints well. Just for your information, the opposite corners of the cube are the same dimension as the outside radius of the sphere.I printed this in the same scale as presented here, and did so with full support enabled. I also printed it without the base structure you see here in these files. I also printed it with no rafting, since I was doing full interior & exterior support. It turned out OK, but took awhile to clean up even with a new Xacto knife blade (and I'm pretty crafty when it comes to using my hands).
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Imported from Thingiverse: https://www.thingiverse.com/thing:14878
Original creator: clintkc