This is my first folding design, so it's not perfect. IT IS TOO THICK TO BEND BY HAND if you use PLA or a material with similar or higher stiffness. You can either make the height axis slimmer on your slicer or use a heat gun to weaken the bend points. If you have an onshape account you can also tweak the CAD model. Link below.
I made this because sometimes buttons got pressed while on my backpack. The solutions here either used too much material and thus printing time for my taste or didn't cover enough (I also wanted to protect the LCD), so I came up with this.
I included a PDF (A4 size) and an SVG (Thangs won't let me upload a DXF) so you can make it out of another material, although paper is way too flimsy for this. Fold inwards from the printed face, so the printed seam lines sit inside the case.
This fit on my Ender 3 Pro's glass bed with a little bit of margin, but I had to watch out for the bed clip placement.
Everything included belongs to the public domain: CC0 1.0 Universal license EXCEPT the PO-20_fold_case.stl file, which contains an approximation of Teenage Engineering's logo which is their protected IP.
You can play with the bottom layer infill pattern to make interesting patterns. I used the "Archimedean chords" pattern on prusaslicer to make those concentric patterns, which fit nicely with the logo pattern.