Inspired by Legos, and other children’s toys like building blocks, the U.S. Marine Corps is building the world’s largest urban warfare training area out in the Mohave Desert of California. There are currently some 400 structures, from private homes, to large government building complexes, erected in the training area. When more money arrives, the “town” will expand to as many as 1,500 structures. What’s different about all this is that shipping containers, equipped with doors, windows, some paint and contents, are being used to represent the buildings. Like Legos, the containers can be joined together, or stacked, to make larger...