We can by Photo-lithography, Laser, Milling, Etching make Intricate Designs on a Single Side Copper Clad Glass Epoxy Board. After that we Multi-Mask the copper side with Translucent Synthetic Lacquer of different shades. Prepare the wall with an epoxy coating and Stick 1 Square Feet panels with tiny rivets or screws. Larger that 1 square feet may cause warp stress, need big screws.
You can also do something that is Geeen. Buy up Surplus Electronics PCBs Old and New with or without Components. After epoxy coating the walls, Fix a thin waterproof hardboard on the wall. Then screw these PCBs as Wall panels, after you have washed, dried and lacquered them.
You can have an entire wall of 286 and 386 Mother Boards or the Boards that come form old Telephone Exchanges full of Relays.