A set of piping tiles that can be placed on or between floor tiles to present the underlying layer of pipes and cables in any heavily pragmatic areas. Factories, water/power plants, the internal spaces of large vehicles, machines, and ships, etc.
The larger tiles can be extended indefinitely and greater variation can be achieved by flipping them along their length.
Additionally, attached is an example of use that I whipped up for my game in a couple of minutes. I placed the floor tiles, The props and then created a layer between the two and added some quick shadows.