I have gotten the idea of building my industrial-everything underground. But it is so dark/saddening under there.
So, I got an idea, for a suggestion... Have you ever seen those digital picture-frame-things that some people have, that cascade from picture-to-picture every few seconds? Well, what if you add a big industrial variant of something like that (multiblock), that is kinda like a painting, but made of blocks, needs power to operate, has a basic control-''computer'', and etc.? It would be similar to Nuclear Control's Industrial Information Panel, except that the computer is not part of the ''frame''.
Usage: The user finds ''holographic-image-chips'' from dungeon/chest loot, and creepers drop them rarely. The chips can be put into the computer, up to 16 of them. An overlay, like Glass, can be selected to make the screen look more realistic. The user can set it to 3 different modes: Single-image (only one image; uses first one in inventory), Cascading (goes from image 1 to 2, then 3, all the way to the last one and then back to 1 and repeat), and Shuffle (Changes images randomly). Modes 2 and 3 can take a timer-setting, from 1 second to an entire hour, and anywhere inbetween.
Display: The screens would have a holographic-effect, kinda like the End Portal blocks, so moving from left to right will make the "stuff" in the holographic image move. Closer objects move more than farther objects, so that it looks realistic. Overworld-images with clouds would have clouds that always move, but simplified (just an animated image; no actual 3d-box or rendering/randomization; it loops like a GIF image; but the image moves like other image-aspects (trees, etc.).
It may be laggy though, so the user can set it to a ''simple'' display mode, that just shows an image on the screen.
That way, we can have screens, that appear to be just like windows, simulating an Overworld field with trees and clouds, when living in an underground industrial-base. Or, we can have a wall of screen, that looks like a nether-area, with reinforced-glass overlays, inside a large workshop/factory suspended a few blocks over a Sulfuric-acid ocean created by industrial pollution.
Reason behind this addition suggestion: Because a stone/stone-blocks/CF/Reinforced-stone wall doesn't look interesting enough, and makes some people/people bored to the point of quitting Minecraft for a while. Also, holographic fake-windows look cool.