Board: t21 to Review with its report; new tasks t29, t33-t36; board updates

- t21 report and subtasks ticked.
- New Todo tasks: t33 telling solid ground from loose grains, t34 nozzle blow reach, t35
  diagonal screw tubes, t36 diagonal wall blocks with a sloped face; t29 added on the board.
- The owner's board edits since the last board commit.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tasks/t21.md

@@ -1,11 +1,22 @@
 ---
 id: t21
-status: Backlog
-order: 3
+status: Review
+order: 0
 priority: P3
 created: 2026-10-24
-updated: 2026-10-24T23:26:09Z
+updated: 2026-10-25T02:42:10Z
 title: Code health: refactor, speed up and test the physics
+report: |
+  (agent) Done in six commits; all tests pass. Water: it did run out, just slowly. Pools now pour
+  off ledges several times faster (a 100-wide pool empties in about 50 s) and leftover film drains;
+  rain from steam spreads out downwind, so a waterfall into a hot shaft no longer refills its own
+  lake. Found and fixed: steam or smoke trapped in a pocket never finished, and rain landing on
+  steam deleted water. Piles near the bot now sort, quickly. Faster with identical results: the
+  roof scan (4.6 -> 1.9 ms on a quiet Huge world) and the heat pass. A loaded world starts around
+  the bot first (Huge, first 10 s: 15 -> 5.5 ms a tick, worst 80 -> 16 ms). Seven duplicates merged
+  and six large files split. Seeds make the same worlds as before. Please check: pour a pond off a
+  ledge; stand by a pile of ore on ash; load a Huge world and fly around in the first 20 s.
+assignee: claude
 ---
 
 ## Context
@@ -14,8 +25,8 @@ title: Code health: refactor, speed up and test the physics
 
 ## Subtasks
 
-- [ ] Remove duplicated code and split the largest modules into smaller files
-- [ ] Profile the simulation and rendering on a Huge world and speed up the slowest parts
-- [ ] A full test pass over water physics in every situation (pools, flows, falls off the world edge, pumps and pipes, freezing and boiling); fix what is wrong
-- [ ] The same kind of pass over sand, molten metal and gases where tests are thin
-- [ ] Fix issues found along the way, and test every piece of gameplay the changes touch
+- [x] Remove duplicated code and split the largest modules into smaller files
+- [x] Profile the simulation and rendering on a Huge world and speed up the slowest parts
+- [x] A full test pass over water physics in every situation (pools, flows, falls off the world edge, pumps and pipes, freezing and boiling); fix what is wrong
+- [x] The same kind of pass over sand, molten metal and gases where tests are thin
+- [x] Fix issues found along the way, and test every piece of gameplay the changes touch