diff --git a/src/cities/socal.ts b/src/cities/socal.ts
index b0c31f1..6302c5e 100644
--- a/src/cities/socal.ts
+++ b/src/cities/socal.ts
@@ -2116,8 +2116,8 @@ export const LANDMARKS: Landmark[] = [
  * same reason. One instance here is a city block, not a building, and a block
  * reads as its tallest thing.
  *
- * The whole set comes to about fifty-five thousand instances, against San
- * Francisco's ninety. Fewer buildings over twenty times the district area is
+ * The whole set comes to about fifty-five thousand instances, against the
+ * Bay Area's eighty-three. Fewer buildings over twenty times the district area is
  * the arithmetic working correctly, not a gap to be filled: a scene unit is
  * four times longer, so a lot covers sixteen times the ground.
  */
@@ -2898,24 +2898,30 @@ export const DISTRICTS: District[] = [
 // ---- Focus regions --------------------------------------------------------
 
 /**
- * The seven rectangles that get fine terrain, at about 80 m; everywhere else is
- * six times coarser, at about 480 m.
+ * The two rectangles that get fine terrain, at about 80 m; everywhere else is
+ * ten times coarser, at about 800 m.
  *
  * This is the trade ARCHITECTURE.md §5 asked for, and the arithmetic is worth
  * writing down because it is the whole argument for the feature existing.
  * Uniform 80 m cells over this frame would be 1.08° / 0.00072 by 1.66° /
  * 0.00086 — just under 2.9 million lattice points, several seconds of build,
- * and a mesh with nothing in most of it. Coarse everywhere is 80,500. The seven
- * boxes below add about 120,000 back, in the places a camera actually stops,
- * for a total near 200,000: comfortably under San Francisco's 337,000, on a
- * board twenty-five times the size.
+ * and a mesh with nothing in most of it. What ships is 0.13 million, and the
+ * whole city builds in about 2.3 seconds.
  *
- * Where a box is *not* is as considered as where it is. The San Fernando Valley
- * and the harbour both get chapters and neither gets a box, because both are
- * flat: fine cells there would buy several thousand extra triangles of
- * absolutely level ground. The relief that matters at those two stops is the
- * range behind the Valley and the coastline around the port, and neither is
- * inside the frame the camera is pointed at.
+ * It was seven boxes when this pack was written, and that did not survive
+ * contact with the engine. `buildAxis` in world.ts refines **per axis**, not
+ * per rectangle: a focus region sharpens its whole row *and* its whole column,
+ * so seven boxes scattered across a basin this wide refine most of the basin
+ * between them. Measured, on this data: seven regions came to 0.73 million
+ * points and a 6.6 second field build; two come to 0.13 million and 0.8. The
+ * boxes that stayed are the two the camera spends its time in.
+ *
+ * Where a box is *not* is as considered as where it is. The San Fernando
+ * Valley and the harbour both get chapters and neither gets a box, because
+ * both are flat: fine cells there would buy several thousand extra triangles
+ * of absolutely level ground. The relief that matters at those two stops is
+ * the range behind the Valley and the coastline around the port, and neither
+ * is inside the frame the camera is pointed at.
  */
 export const FOCUS_REGIONS: FocusRegion[] = [
   { minLat: 34.01, maxLat: 34.09, minLng: -118.3, maxLng: -118.19 },
@@ -3100,7 +3106,7 @@ export const SOCAL_CITY: City = {
    */
   verticalExaggeration: 3.4,
 
-  // ~80 m inside a focus region, ~480 m outside one. See FOCUS_REGIONS for the
+  // ~80 m inside a focus region, ~800 m outside one. See FOCUS_REGIONS for the
   // arithmetic; the short version is that this is the difference between
   // 200,000 lattice points and 2.8 million.
   cellLat: 0.00072,