Summary

This is a work in progress, I'm open to feedback.

Inspired by https://www.thingiverse.com/thing:3901517 but adds baseplates on which the hexagons kind of clip wherever you want and laser cut transparent acrylic windows.

You can probably get acrylic laser cut for relatively cheap if you order a large enough quantity.

I'm still not 100% sure about the wall mounts. The problem is that each plate of 9 hexagons would require 2 screws. The fix, which I haven't fully validated yet, is small connectors that can help attach two plates together. I think they might also provide a nice staircase effect to the displays.

The author of the work is https://www.thingiverse.com/arnaud16/designs 
Source : https://www.thingiverse.com/thing:6416662