Resting faces steeper than the angle of repose topple: blown sand towers collapse (t93)

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

docs/PROJECT_MAP.md

@@ -225,9 +225,9 @@ Material definitions: ids, properties and metal families. ids, and drill/tank ti
 - functions: def, metalFamily
 - variables: EMPTY, GRASS, DIRT, LDIRT, SAND, GRAVEL, CLAY, STONE, GRANITE, BASALT, NMAT, MD, FIRETO
 
-### src/sim/material-tables.js (54 lines)
+### src/sim/material-tables.js (55 lines)
 Material tables: typed properties, casting groups, flags, parts and tool tiers. Typed property tables
-- variables: PH, DENS, KC, ICAP, CASTMETAL, METAL_TIER, SOLIDMETAL, F_NAT, F_CAST, F_BURN, P_NONE, P_SCREW_U, P_SCREW_D, P_SCREW_L, P_SCREW_R, P_GRATE, P_GOPEN, P_WHEEL, P_INTAKE, P_FILTER, P_PIPE, P_SCREW_UR, P_SCREW_DR, P_SCREW_DL, P_SCREW_UL, SCREW_PARTS, SCREW_DIRS, IS_SCREW, SCREW_DX, SCREW_DY, BIT_TIERS, TANK_TIERS, REACH
+- variables: PH, DENS, KC, ICAP, CASTMETAL, METAL_TIER, SOLIDMETAL, F_NAT, F_CAST, F_BURN, F_AVALANCHE, F_AVALANCHE_R, P_NONE, P_SCREW_U, P_SCREW_D, P_SCREW_L, P_SCREW_R, P_GRATE, P_GOPEN, P_WHEEL, P_INTAKE, P_FILTER, P_PIPE, P_SCREW_UR, P_SCREW_DR, P_SCREW_DL, P_SCREW_UL, SCREW_PARTS, SCREW_DIRS, IS_SCREW, SCREW_DX, SCREW_DY, BIT_TIERS, TANK_TIERS, REACH
 
 ### src/sim/pieces.js (179 lines)
 Everything the player can build (PIECES): blocks, machines and molds, with costs and descriptions; filter settings; wall materials and their cost.
@@ -254,9 +254,9 @@ Exploration only: never changes grains or the random stream.
 - functions: fogAlloc, fogMark, fogSeen, fogInit, fogLook, fogRevealAround, fogRevealAll
 - variables: FOG, FOG_SENSE, FOG_SENSE_FADE, fog, FW, FH
 
-### src/sim/cells.js (272 lines)
+### src/sim/cells.js (321 lines)
 Cell helpers (setCell, move, enter) and the falling-sand movement of powders, liquids and gases (simMove).
-- functions: setCell, swapCells, swapCellData, move, enter, enterFree, powder, passable, liquid, liquidSearch, gas, wakeBotPowder, simMove, moveChunk
+- functions: setCell, swapCells, swapCellData, move, enter, enterFree, powderSpill, avalancheMove, powder, passable, liquid, liquidSearch, gas, wakeBotPowder, simMove, moveChunk
 - variables: SORTP, SORTP_FUEL, LSTEP, LFILM, CORNER_SEAL, POWDER_FAN
 
 ### src/sim/heat.js (266 lines)
@@ -630,11 +630,14 @@ The frame loop and boot.
 - `test/harness.js`: Loads the simulation (the src/sim/ files listed in src/manifest.json, joined in order into one script, the same way build.py joins them) so scenarios can drive it headlessly in Node. Errors point at the real file and line (sim/pipes.js:42), not at the joined script.
 - `test/light-cases.js`: Lighting behaviour checks executed by the GPU browser harness.
 - `test/light-readback.js`: Read float source channels, including transmittance, from the WGSL light pass.
+- `test/pile-blow.js`: Shared reproduction: continuously blow plain bagged sand straight above a stationary bot.
 - `test/pile-cut.js`: Shared Node/browser reproduction: vacuum the foot of settled 60-grain heaps, one stroke per tick.
 - `test/play.py`: Play-test in a real browser: mouse, keyboard and a mocked gamepad drive the game; save and continue. Screenshots go to shots/play/ (or the folder given as the first argument). Pixel look unless the second argument is 'smooth'.
 - `test/run_all.py`: Run the test suites and report.
 - `test/t_bar_stacking.js`: Resting bars snap into pairs of grains and tip off narrow supports.
 - `test/t_basics.js`: Basics: drilling to rubble, the vacuum and blowing, walls, the ingot mold and bars, belts, blueprints, save/load.
+- `test/t_blow_collapse.js`: Owner's upward nozzle recipe, inline and with real shared-memory helpers.
+- `test/t_blow_collapse.py`: Straight-up bagged sand nozzle in the real pixel frame loop.
 - `test/t_build.js`: Building: undo (Ctrl+Z), cut, replace a machine with Ctrl, pasting ghosts, and the fan heat warning.
 - `test/t_caps.py`: Capability detection, title notices and the required-WebGPU startup gate.
 - `test/t_conveyors.js`: Screw conveyors that never carry liquid (it flows through), screw and belt throughput, filters.