How about wallpaper?

[KevinWalter]

It's really common to spam paintings and statues all over the place to increase decor rating and keep dupes calm. But what about wallpaper?

It wouldn't have to add a huge amount of decor, but it would serve two functions. Adding SOME decor in order to reduce the need for so many paintings/statues (both of these items should still provide more decor per tile than wallpaper), but if there were a few different colors of wallpaper, it would be great from the player's perspective as a sort of label. 

For instance, if you have reddish colored wallpaper, you might place that in your "industrial zone" where you keep things like generators. Maybe you like green wallpaper, so maybe you use that to color your living quarters. Even a bunch of simple colors that simply add a slightly different hue to the plain background could function as this "wallpaper".

It would probably have to be applied in the same fashion as wires... so it's able to go "behind" objects on its own layer of the Z axis (not sure how the devs reference this aspect of the game), while being occluded visually by anything placed on on a closer layer, such as painting, structures, etc. Just like wires and pipes and everything else that can be hidden within tiles and behind objects like ladders. 

The only real downside I can see for this is it might make it slightly difficult to see the distribution of gases depending on which colors you use... but isn't that what the overlays are for anyway?

[x4550]

There was a very good post about that here