If three walls are angled (say at 15 degrees or so) and are bolted together, then they're not going to fall down. Because of building permits, I cannot anchor the Potemkin bridge to the walls of the garage. Instead, they're anchored to each other and to the raised platform deck they're sitting on. You literally could attach a chain to the edge of the bridge set and wench it out of the garage. It might get stuck on a step, but a lever could be used to lift that portion around. Once outside, it would still be standing.