This is modeled after the original English butler's tray. The sides are folded up so the butler can bring the tray to the stand. Then the sides are folded flat to become a small table for eating. A forerunner to today's TV trays.
It is printed in place with hinges. When folding up the sides insert short pieces of printer filament to pin the corners together.
I made this as large as is possible to still fit on my Ender 3 print bed (235x235), you can scale it but if you go too small the hinges will probably be seized up due to tight tolerances.
The included pictures don't do it justice but I ran into printer problems that prevented me from getting a good quality sample to photograph…
The author marked this model as their own original creation.