A kamishibai (japanese storytelling theatre for kids), with 3 doors style and an insert to keep the whole thing enclosed.

The doors have holes for little magnets (4 in total) to hold onto each other.

I designed mine for my little girl, so I added a floral pattern and a gemstone lock (with a 20 in roman numerals because of the nerd I am)... not that she cares for now, she is just 2, but I got a little carried away, and I believe in overdesigning as a form of fatherly love.

I am also including plain insert and doors, so you can customize it at leisure or at least do away with the roses.

The size is made to accomodate A5 paper, because I could not print an A4 version anyways on my Ender-3, but if you can go bigger, I don't see why it could not scale up nicely.

If you scale up you also get the added benefit of more forgiving hinges. I broke two of mine during assembling, so in the stl here I added a little more clearance, I cannot overdo it because there is nothing but friction holding the doors open, especially the upper one.

In any case, since the broken ones are not on the same side, the remaining stubs plus the surviving pin still do the job without having to reprint the frame, so don't panick if it happens to you too.