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/t36_diagonal_wall_blocks.md

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+---
+id: t36
+title: Diagonal wall blocks with a smooth sloped face
+status: Todo
+created: 2026-10-25
+updated: 2026-10-25T02:45:20Z
+---
+
+
+
+## Context
+
+- Walls can only be placed on the square block grid, so a sloped wall is a staircase of blocks. Grains catch on every step instead of sliding down, which makes funnels and hoppers clog. Add diagonal wall placement, and wall pieces whose face is a flat 45° slope, so loose material slides smoothly down a funnel wall.
+
+## Subtasks
+
+- [ ] Add sloped wall pieces: half-block triangles in the four orientations, so a run of them makes a flat 45° face
+- [ ] Dragging a wall line at 45° lays a diagonal run of sloped pieces; R picks the orientation for a single piece
+- [ ] Grains, liquids and bars slide down the flat face without catching (check powder sliding and the STICK rule against a straight 45° line)
+- [ ] Works with every wall material; refunds, copy, cut, paste, undo and blueprints handle the new pieces
+- [ ] Tests: sand poured into a V funnel of sloped walls all comes out the bottom; the same funnel built from square steps for comparison