ABC's of Modular Modules. I am building trackside industries using DPM wall modules intermixed with kits from DPM and other manufacturers. (Actually anything I see cheap enough I will buy for parts if I can use it later). When I put the kits together I finish the unseen walls so that each segment can stand by itself as a separate building if need be. I make the buildings so that I can put them side by side longwise or shortwise depending on how I need them to fit into the actual layout. If I want to move them to another location later, I have more latitude in what I can do. While I am designing the buildings, I make isometric ******** drawings, but they don't always give a perfect idea of what the building will look like on the layout, even if I make all four views. I needed something that I could look at from every angle. I bought children's ABC blocks (approximately 1" square) and painted the sides red and the tops black. I put them together in the same configuration as the proposed building, and put rubber bands around each little sub building on every floor. I can look at the structure from all angles and see what is the most plausible for my needs, and get a good idea of how the finished product will be. If I want to make changes, it's easy to put blocks in, take them out, and rewrap them.