When it's sealed, this perplexing container appears to have three intersecting dovetail joints. In reality, the joints curve so you can twist off the lid. I think it makes a pretty fun container for any little trinkets.
If you want a tricky box that locks, check out my other Dastardly Dovetail Puzzle Boxes!
Photographed model was printed with MatterHackers Quantum PLA (Also on Amazon)