I got this puzzle as a present and was surprised I didn't see the model here on Thingiverse. I checked but couldn't find any patent or license so assume I was free to make model and post it here. If anyone knows better, please let me know and I'll act accordingly.
Difficulty: ★★★★★ (whatever that means)
Print the piece 24 times and have fun! Freecad model included.
I compensated 0.5mm to compensate for overextrusion and better fit without post processing.