Diagonal screw tubes, laid by a 45° drag (t35)

- Tubes run in eight directions: a drag at about 45° lays a diagonal run, R cycles all eight.
- Diagonal runs carry grains at the straight rate (120 grains/s), join straight tubes and belts,
  keep grains in at the corners, pass water, and carry bars level.
- New part ids 11-14 (saved ids are never renumbered); tube checks use an IS_TUBE table.
- New test/t_diag_tubes.js (85 checks).

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

docs/DESIGN.md

@@ -373,6 +373,11 @@ above, including:
   would otherwise slip through where two pieces meet). Square walls placed diagonally still
   touch only at corners and leak there, like any square blocks.
 
+- **Diagonal screw tubes (t35, 2026-10-25).** Tubes run in eight directions. A drag at about 45°
+  lays a diagonal run pointing along the drag, and R cycles all eight for a single tube. Diagonal
+  runs carry grains at the same rate as straight ones, join straight tubes and belts, and carry
+  bars level, a block every eight ticks. They use new part ids (11-14) because part ids are saved.
+
 ## Ideas not built yet
 
 - **Concrete**, as a stronger wall material from rubble.

docs/PROJECT_MAP.md

@@ -201,9 +201,9 @@ 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 (49 lines)
+### src/sim/material-tables.js (54 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_TU, P_TD, P_TL, P_TR, P_GRATE, P_GOPEN, P_WHEEL, P_INTAKE, P_FILTER, P_PIPE, TDX, TDY, BIT_TIERS, TANK_TIERS, REACH
+- variables: PH, DENS, KC, ICAP, CASTMETAL, METAL_TIER, SOLIDMETAL, F_NAT, F_CAST, F_BURN, P_NONE, P_TU, P_TD, P_TL, P_TR, P_GRATE, P_GOPEN, P_WHEEL, P_INTAKE, P_FILTER, P_PIPE, P_TUR, P_TDR, P_TDL, P_TUL, TUBE_PARTS, TUBE_DIRS, IS_TUBE, TDX, TDY, BIT_TIERS, TANK_TIERS, REACH
 
 ### src/sim/pieces.js (158 lines)
 Everything the player can build (PIECES): blocks, machines and molds, with costs and descriptions; filter settings; wall materials and their cost.
@@ -240,7 +240,7 @@ Heat: conduction, melting and freezing, reactions, fire and air, steel.
 - functions: curAir, airflowAt, alloyMix, airy, hasO2, condPair, heatPass, heatChunk, neighborDir, react, char, quench, burningNear, burn, steelCheck
 - variables: POROUS, SOIL, HOTLIQ, REACT_MIN, ALLOY
 
-### src/sim/machines.js (148 lines)
+### src/sim/machines.js (157 lines)
 Machines: the power network, footprints, placing and removing machines.
 - functions: markPow, partLost, rebuildPower, netSat, evictCells, cellBuildable, machineFootprint, canPlaceMachine, addMachine, removeMachine
 - variables: nextPowerBuild
@@ -260,13 +260,13 @@ Pipes, pumps and outlets: each joined line holds one liquid as a count, not as g
 - functions: sideOf, pipeClosedSide, pipeJoins, rebuildPipes, pipeNetOf, pipeTakeShare, faceCell, pumpDraw, outletPour, pipesTick
 - variables: PIPE_CAP, PUMP_RATE, OUTLET_RATE, PUMP_MAX_T, SIDE_V, PUMP_V, OUTLET_V, pipeNets, pipeNetAt, pipesDirty
 
-### src/sim/machine-tick.js (164 lines)
+### src/sim/machine-tick.js (168 lines)
 Per-tick machine work: steam engines, fans, belts, filters, screw tubes (machinesTick).
 - functions: engineIntake, fanBlow, machinesTick
 
-### src/sim/conveyors.js (128 lines)
+### src/sim/conveyors.js (147 lines)
 How belts, filters and screw tubes move what is on or in them. What rests on a belt or filter rides along: the whole stack standing on the carrying surface steps one cell toward d together (belts run front of the line first, so the way ahead is clear). If a powder grain is blocked, the load above it stands still and the belt slips underneath. A filter's own material drops through it instead, unless it is already full.
-- functions: carryColumn, beltDrain, launchGrain, rebuildFilters, filterCarry, setFilter, filterRun, roomFor, tubeSpread, tubeIntake
+- functions: carryColumn, beltDrain, launchGrain, rebuildFilters, filterCarry, setFilter, filterRun, roomFor, tubeSpread, tubeIntake, diagonalTubeNext
 - variables: CARRY_DEPTH, filterR, filterL, filtersDirty
 
 ### src/sim/blocks.js (208 lines)
@@ -278,9 +278,9 @@ Molds: cavities for castings; ingot troughs empty themselves below. Removal retu
 - functions: moldCellsAt, canPlaceMold, newMoldRecord, addMold, castMix, cavityState, troughState, clearCavity, moldPlugCells, rakeAbove, furnaceJunkHint, unplugMold, ejectIngot, checkMolds, moldAt, tally, collectMold, removeMold
 - variables: DROSS, grains, barWord
 
-### src/sim/items.js (232 lines)
+### src/sim/items.js (256 lines)
 Bars and other loose objects (ents), and the bag: adding, taking, costs and refunds.
-- functions: entSolidCell, entSupportCount, entFreeAt, entMark, spawnBar, removeEnt, entTubeAt, entTubeFree, entTubeMove, entTubeLane, entTubeEdge, entTubeEnter, entTubeTick, entTick, entsInCircle, bagAdd, bagTake, giveOrDrop, refundAt, canAfford, payCost, fmtMoney, costText, needText
+- functions: entSolidCell, entSupportCount, entFreeAt, entMark, spawnBar, removeEnt, entTubeAt, entTubeFree, entTubeMove, entTubeLane, entTubeEdge, entTubeEnter, entTubeTick, entDiagonalTubeTick, entTick, entsInCircle, bagAdd, bagTake, giveOrDrop, refundAt, canAfford, payCost, fmtMoney, costText, needText
 - variables: BAR_W, BAR_H, entCurM, droppedLast
 
 ### src/sim/tools.js (52 lines)
@@ -356,7 +356,7 @@ Drawing (src/render/): browser only. This file: the renderer state R, colour tab
 Propagated coloured light from glowing and burning cells.
 - functions: builtForLight, computeLight
 
-### src/render/world.js (330 lines)
+### src/render/world.js (332 lines)
 Scale colour without changing the smooth-look class.
 - functions: fogColor, drawWorld
 - variables: TUBE_CLASS
@@ -374,7 +374,7 @@ Smooth look: WebGL setup, texture uploads, drawing and adaptive resolution.
 - functions: smCompile, smoothAvailable, smUpload, smoothDraw, smoothPace
 - variables: SM, smBytes
 
-### src/render/smooth-shaders.js (337 lines)
+### src/render/smooth-shaders.js (342 lines)
 Smooth shaders: vertex and fragment programs for the rounded world look.
 - variables: SM_VS, SM_FS
 
@@ -448,7 +448,7 @@ Selection panels: current tool card and bag materials.
 - functions: renderSelCard, renderBag
 - variables: lastBagKey
 
-### src/ui/info.js (188 lines)
+### src/ui/info.js (189 lines)
 Discovery cards, hover info (I) and the cursor label.
 - functions: showCard, howText, discoveryCard, reactionsOf, hoverInfo, renderInfo, drawCursorLabel, pipeContentsText
 
@@ -457,7 +457,7 @@ Keyboard and mouse listeners.
 - functions: isTyping
 - variables: canvas
 
-### src/ui/actions.js (239 lines)
+### src/ui/actions.js (240 lines)
 What input does: overlays, F, pick, copy / cut / paste, undo, building and tool use each frame. Which overlays are on, shown as a coloured frame round the screen and a named badge
 - functions: updateOverlayUI, toggleLens, doInteract, pickUnderCursor, aimBlock, stampOrigin, selModeHeld, startPaste, stopSelectAndPaste, plural, piecesIn, doUndo, endRmbRecord, dragDirFor, blockLabel, primaryPress, primaryRelease, secondaryPress, toolTick
 - variables: ovShown
@@ -505,6 +505,7 @@ The frame loop and boot.
 - `test/t_basics.js`: Basics: drilling to rubble, the vacuum and blowing, walls, the ingot mold and bars, belts, blueprints, save/load.
 - `test/t_build.js`: Building: undo (Ctrl+Z), cut, replace a machine with Ctrl, pasting ghosts, and the fan heat warning.
 - `test/t_conveyors.js`: Screw tubes that never carry liquid (it flows through), tube and belt throughput, filters.
+- `test/t_diag_tubes.js`: Diagonal screws: sealed four-lane corner transfers, bars, joins and persistence.
 - `test/t_drill.js`: The resonance drill: pulses from the bot shake rock until it shatters. Widths trade area for speed, tuning shatters only one material and drains it out of the wall, built blocks are left alone, and the drill says why when nothing breaks.
 - `test/t_econ.js`: Economy: the dock (instant sale), orders, prices, the market dip, money for machines, alloys.
 - `test/t_fog.js`: Fog: surface, sight, range, saves and simulation independence.
@@ -545,4 +546,5 @@ The frame loop and boot.
 - `tools/scenes/silo.js`: Run after clear-sky.js; leave paused so the open gate keeps its demonstration charge.
 - `tools/scenes/stone-uses.js`: The stone and sand machines: a half-full silo with its gate open over a belt, a stone cutter fed with rubble, and cut stone and glass brick walls. Run clear-sky.js first, e.g. python3 tools/shot.py /tmp/stone.png --setup tools/scenes/clear-sky.js --js "$(cat tools/scenes/stone-uses.js)" --ticks 240 --zoom 7
 - `tools/scenes/t33-ground.js`: Paused dug pocket: copper ore, rubble and dirt against stone, granite and dirt. Use --js "..." to set daylight or R.lens after this setup; CAM frames the pocket.
+- `tools/scenes/t35-diagonal.js`: Run after clear-sky.js: a belt takes sand from a pile, up a diagonal screw to an upper belt.
 - `tools/scenes/t36-funnel.js`: A twelve-block funnel, one block open at the bottom, draining 400 grains of sand.

docs/agent-log.md

@@ -4,6 +4,17 @@ What agents have done, newest first. Add an entry for every piece of work: the d
 note or request it was for, what changed, the files touched, the tests run, and anything left
 open or not verified. Keep each entry short; the git history has the details.
 
+## 2026-10-25: t35: diagonal screw tubes (Claude Code, Codex)
+
+- Parts `P_TUR`..`P_TUL` (11-14), `TUBE_PARTS`, and an `IS_TUBE` table replacing every
+  `P_TU..P_TR` range check (`src/sim/material-tables.js` and its users); tube variants 4-7;
+  diagonal drags for tubes; grains in `src/sim/conveyors.js`/`cells.js`, bars in `items.js`;
+  both looks, previews, hover, copy/paste, undo, blueprints, saves.
+- `test/t_diag_tubes.js` (85 checks): 120 grains/s straight, up and down over ten blocks; joins,
+  no spills, water passes, bars both ways, controls, persistence. Existing suites unchanged and
+  passing; seeds unchanged. `run_all.py --browser` ALL PASSED. Screenshots
+  `shots/t35-diagonal-*.png`, scene `tools/scenes/t35-diagonal.js`.
+
 ## 2026-10-25: t36: sloped walls and diagonal wall lines (Claude Code, Codex)
 
 - `BP_SLOPE_BL`..`BP_SLOPE_TR` (15-18) in `src/sim/pieces.js` (`isSlope`, `isWall`, `slopeCell`,