This is a simple and lightwight insert for the boardgame Mycelia by Ravensburger (German/European version).
To fit on the bed the top part can be diveded into two parts (as shown on the photos).
The lids of the boxes consists of two parts too, the center part can then be printed without bottom or top layer to get only the infill. At the picture you can see honeycomb with 15 % infill.
The author remixed this model.
Model served as orientation and inspiration.
Adaptation of the fields to keep the parts for the solo play so that no additional layer (at the bottom) is required.