UPDATE: here is a link to my OnShape design, which I have parameterized.  You can change the overall dimensions of the box and export new STL files: [https://cad.onshape.com/documents/89ee1fae0b44d3ba51374deb/w/8c6c8751f8fadaf05afa6176/e/335e7697609945060bea23a9](https://cad.onshape.com/documents/89ee1fae0b44d3ba51374deb/w/8c6c8751f8fadaf05afa6176/e/335e7697609945060bea23a9)

A box you fold up like cardboard. Final size is approximately 50x50x25mm, so fairly small but fits on most printers. Well suited to dual color, use one color for the first two layers, which will be on the outside of the box, and a different color for the next two layers (inside).

Print Settings

Resolution: 0.1, 0.2 first layer (4 layers total)

Infill: 100%

Material: Anything that can take a 90° bend, tested on PLA and PETG so far.

Notes: PETG seems to take the bends better than PLA, but both work.