Cubic shell with corners chopped. Best printed resting on a corner with a brim. Can nest multiples in the same print to create linked cubes. (Included g-code is for a single cube.) Prints well in PLA on MK3s - your results may vary.

Print instructions

To print interlocking cubes, place the first cube on the build-plate in Prusa Slicer, copy it, & move the copy so that none of the structures of the cubes overlap. You can check for overlap after slicing using the layer slider. Don't forget to use a brim.

I've added g-code for 2 linked cubes on a brim in the "User Files" section.