Most first cities in Terrace Nine die of a heat deficit around day forty. Here is a layout that does not, and the reasoning behind every part of it.
Terrace Nine gives you every number you need and almost no advice about what to do with them, which is why so many first cities collapse in the same way: a heat deficit that arrives around day forty, well after the decisions causing it have been buried under three terraces of construction.
The fix is to treat heat as the constraint everything else bends around, rather than a utility you add later. Place the geothermal tap first and build housing outward from it in rings, keeping every block within two segments of the main line. It will look inefficient on the terrace map. It will also still be standing in the second winter.
From there, hold your third terrace empty until the first two run a surplus for ten consecutive days. The instinct to expand the moment you can afford to is exactly what turns a comfortable city into a fragile one, because expansion adds demand immediately and capacity only after a build cycle.
