One built volume, one real thing.
The rule that makes the whole thing work, and the one that was hardest to keep. No building is ever invented to fill a gap. A habitat dome is a project answering HTTP right now; a greenhouse is a repository; an ice extractor is a Stripe account. Few things means a small colony — and it grows on its own as you ship, without anyone laying out a map. The only volumes with nothing behind them are landscape, and the world says so out loud: matte rust, never data.