Shelf for Honeycomb
you will need two screws and two nuts M5, and the M5 insert from
https://files.printables.com/media/prints/152592/stls/1435365_24caa3a9-ad43-49bf-aada-7852a163a353/insert-m5.stl
Honeycomb accessory:
https://www.printables.com/model/152592-honeycomb-storage-wall/files
The author remixed this model.