When you got the Rainbow box coin I thought that it was a mini-version of the puzzle... Can you imagine if someone made a nested puzzle box like the nested dolls? That would be cool and perhaps even a bit funny! Okay, so for my vote for next puzzle you to do the other one that neither of us can pronounce and send the LOKI to the LPL, LOL
I think this is an incredible puzzle, I'm not a big fan of 3D printed material, and I think that would put me off buying it. I've seen companies that take the 3D .stl file and machine it from alloys on a CNC machine. Id definitely consider buying a metal version.
