This is a (very) difficult puzzle with 12 identical pieces.
Once assembled, they form a cube.
The difficulty comes from the fact that all pieces must fit "at the same time"...
My version has no gap, so it is quite difficult to undo the puzzle. The uploaded version has a 0.2mm gap.
It was printed with one color only.
Feedbacks and multi-color pictures are welcomed.
Trick: there is a trick to solve the puzzle. Start with the 4 corners (a set of three pieces), with the same orientation. Then you can assemble the 4 corners. So, actually, it is not 12 pieces at the same time, but rather 4*3 pieces.
The solution can be found here: https://youtu.be/wv2J_S8axNA