The water arc, carried since Sprint 3. Rain (Lane C's rainMmPerHour x the
exported RAIN_TIME_COMPRESSION, never hardcoded) lands on each node's
horizontal projection, runs down its steepest of 8 neighbours, and pools
where it can't get out. A flat sail's belly is a basin water flows into
and can't climb from; a hypar drains along its saddle ridge to the low
corners and off — so ponding cannot pincer §7, and measured on real yard
quads a flat rig holds 12 kg/m² vs a twisted rig's 1.7.
The 8-neighbour graph is load-bearing: a 4-way one can't follow the
saddle's diagonal ridge, so it trapped water in the gravity belly and a
hypar pooled as much as a flat sail. Steepest-GRADIENT descent (not
steepest drop) because a diagonal is √2 farther.
Gate 1, in asserts: a flat carport rig under a capped wind survives dry
(4/4) and dies wet (a corner at t=85s) — the control isolates water from
wind — and the broom saves it. Plus dump-on-break, dump-on-tension-up
(the turnbuckle counter-play), mass conservation, and a belly-tear safety
valve at 4 m of sag.
API for D and A, frozen in contracts.js: pondMass(), pondCentroid(),
drainPondAt(node, dt) -> kg-on-your-head. session.reset() for A's "play
again".
On D's tn-1.04 cliff: investigating it IS what surfaced the ponding load
regime. The 10 kN "spike" is real physics, not solver divergence — a
155 m² flat sail holding 2100 kg of water genuinely pulls ~21 kN, stays
finite, and tracks the water. So no physics-altering clamp (the
displacement clamp I tried moved the thesis 39->34%); instead an opt-in
`watchDivergence` tripwire that throws with a repro above 80 kN, live in
every selftest rig and never false-tripping, and a belly-tear that bounds
the runaway physically. Full writeup for D in THREADS.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Rebased onto M0 and reconciled against the real spine. checkContract
('sailRig') now conforms and js/tests/b.test.js runs 28 asserts green.
Contract fixes:
- anchor.sway(t) is the ABSOLUTE position, not an offset (thanks A —
I had it adding sway to pos, which would have flung every
tree-anchored corner to double its coordinates).
- events is an Emitter emitting {type, corner}, not a drained array.
- coverageOver() rects are centre+size, matching world.gardenBed. It
consumes world.sunDir directly: a hit along sunDir means shaded.
- START_BUDGET/SPARE_COST/HARDWARE/FIXED_DT now come from contracts.js
rather than being redeclared here.
Bug: a corner that blew was marked broken but never had its mass
returned, so invMass stayed 0 and the "blown" corner sat welded in
mid-air — no flogging, and the sail silently went dead. PLAN3D §5-B
wants flogging emergent from the freed node, so _checkFailure now frees
it. The cascade test missed this because it called _repin() by hand;
the new test drives a real overload failure instead and asserts the
corner tears 2 m off its anchor and keeps moving.
Tension dial remapped from the prototype's rest/tension to a real
pre-strain. rest/tension asks for 17% strain at dial 1.2 and 29% at 1.4
— stretching an 18 m sail by three metres — and put 68 kN on a corner of
the yard's biggest quad with no wind blowing. At 0.10 strain-per-dial it
swings a 5x5 rig's peak load 2.1x loose-to-tight and redlines a 192 m2
quad at 8.3 kN drum-tight, which is punishing and correct.
HARDWARE ratings retuned in contracts.js to real newtons per the
standing note there that Lane B owns these numbers. Costs and tier shape
untouched; $80 still buys rated hardware on at most 2 of 4 corners.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Ports the prototype's economy verbatim: $80 budget, $5/$15/$30 hardware
tiers, $15 spare, tension 0.6-1.4. Adds unrig-with-refund, which the
prototype lacked — a misclick there was unrecoverable, and a full refund
costs the economy nothing.
RiggingSession holds all the rules and is three-free and DOM-free, so it
tests headless. The picking UI is left as an explicit seam: it needs Lane
A's camera and anchor markers to raycast against, which do not exist yet.
One assert encodes a design invariant rather than a code fact: $80 must
not buy rated shackles on all four corners. DESIGN.md's economic tension
is that you always field one dodgy corner and choose which one; if that
test ever passes, the budget has become decoration.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
