acdream/docs/plans/2026-07-29-physics-parity-campaign.md

# Campaign P — Physics Retail-Feel Parity

**Filed:** 2026-07-29. **Directed by the user** as a pre-vendor-management
detour after the same-day physics/collision retail-fidelity audit. The
world-interaction program (Slice 5, vendor browsing) resumes when this
campaign closes.

**Execution model:** Claude drives autonomously slice-to-slice. Sonnet
subagents implement bounded chunks against this plan's specs; an Opus
review subagent gates every slice boundary. The only user stops are
(a) the final batched connected visual matrix, (b) a DO-NOT-RETRY
conflict, (c) anything destructive. All the CLAUDE.md workflow rules
apply: grep-named-first → pseudocode → port → conformance test; register
moves in the same commit; no workarounds.

---

## The parity goal (the autonomy contract)

**"Retail Movement Parity v1"** — the campaign is DONE when all of the
following are auditable-true:

1. **Zero physics-scope temporary stopgaps.** TS-1, TS-4, TS-5, TS-23,
   TS-46 retired by porting the retail mechanism. TS-24, TS-35, TS-40
   either retired or re-classified (IA/AD) with a recorded justification.
2. **No feel-affecting approximations left unargued.** AP-7 resolved by
   decoding retail's friction state gate; AP-10 restored to retail's
   0.1 m water sink-in; AP-25 replaced by the retail effective-skill
   chain (vitae/enchantment-aware); AP-71 (`check_entry_restrictions`)
   ported.
3. **Issue ledger:** #262, #165, #166, #116, #167, #72, #153 closed;
   the stale "pending visual gate" statuses on #172/#173/#174/#175/#41
   reconciled (folded into the final matrix below). Explicitly excluded:
   #235 (user-deferred 2026-07-27) and #256/#257 (lifecycle/memory, not
   physics feel — separate track).
4. **Verification:** each port carries decomp citations + conformance
   tests; `dotnet build` + full Release suite green at every slice
   commit; one batched connected visual matrix (below) passes at the
   end, run by the user.

Anything not in this list is out of scope for the campaign — file it,
don't chase it.

---

## Slices

### P1 — Stat-coupled movement (burden / stamina / vitae) — retires TS-5, AP-25, the burden gap

**Status (2026-07-30): COMPLETE.** Landed at `9355ddce`; Opus review
APPROVE at `001e466d` (which also retired UN-8 — the CanJump polarity is
byte-PROVEN `load < 2.0` from the PDB-paired binary — and recorded the
PK-timer jump-cost decode for P3). Full Release suite 9,880/0/5 at the
slice gate. Retail's vitae/enchant chain reuses the M3 bucket-4
representation; `JumpStaminaCost` never refuses (weak-jump only) — the
plan's formula shorthand had the `+0.5` operand wrong and the
implementation follows the decomp's `(load+0.5)*power*8+2`. AP-127 was
filed for the then-bounded bonus properties and retired by #268 on
2026-07-31.

Today `PlayerWeenie.SetBurden` has zero callers, `CanJump` is always
true, `JumpStaminaCost` is 0, and pushed run/jump skill is
attributeBonus + init + ranks only. Retail modulates movement by
character state continuously.

**Retail anchors (named decomp, verified 2026-07-29):**
- `ACCWeenieObject::{CanJump 0x0058c400, JumpStaminaCost 0x0058c440, InqJumpVelocity 0x0058c520, InqRunRate 0x0058c560, InqMaxRunRate 0x0058c5a0}` — thin delegations to the qualities DB (pseudo-C ~406512).
- `CACQualities::{InqMaxRunRate 0x00591b20, CanJump 0x00591b50, JumpStaminaCost 0x00591b90, InqRunRate 0x00592800, InqJumpVelocity 0x00592980, InqLoad 0x0058f130}` (pseudo-C ~412901–413975, ~409756) — the real load/skill/vitae composition. `InqJumpVelocity` ends in `sqrt(GetJumpHeight(...) * 19.6)` (pc 413975).
- `MovementSystem::{GetRunRate 0x006b0950, GetJumpHeight 0x006b09b0, JumpStaminaCost 0x006b0a40}` (pseudo-C ~695958) — GetJumpHeight readable: `LoadMod(load) * (skill/(skill+1300) * 22.2 + 0.05) * power / scaling`, floor 0.35; JumpStaminaCost readable: `ceil(((power + 0.5) * load) * 8 + 2)` on the arg3==0 branch.
- `EncumbranceSystem::{EncumbranceCapacity 0x004fcc00, Load 0x004fcc40, LoadMod 0x004fcc70}` (pseudo-C ~256393).
- Cross-refs: ACE `MovementSystem`/`EncumbranceSystem` C# ports; holtburger if it models load.

**Work:**
1. Port the full chain into Core (`EncumbranceSystem` + `MovementSystem`
   statics; `PlayerWeenie` becomes the CACQualities-shaped composition).
   Where BN x87 mush blocks a branch (GetRunRate body), use Ghidra MCP
   or the ACE port as the tiebreaker and cite which.
2. Determine, from `CACQualities::InqRunRate`'s own body, exactly which
   skill level retail feeds (base vs enchantment/vitae-adjusted) and
   port THAT — scoped to the run/jump query path only, reading vitae +
   relevant skill enchantments from the M3 active-effect state. Do not
   build a general effective-skill engine.
3. Plumb the inputs from Runtime: burden (EncumbranceVal/capacity from
   PlayerDescription + property updates), current stamina (vitals),
   vitae. Extend `RuntimeMovementSkillState` (J4.4 seam) so updates flow
   mid-session, same as run/jump skill today.
4. Wire the existing `jump_is_allowed` stamina-refusal branch and the
   `ReportExhaustion` dual-dispatch gate (R3-W4 seam) to a real
   consumer, matching retail's refusal/weak-jump behavior.
5. Conformance tests: formula tables (golden values incl. 800-skill cap,
   load-mod knees at 100%/200%, stamina cost ceil), gating tests
   (no-stamina jump refusal), plumbing tests (burden/stamina/vitae
   changes move the produced rate). Register: delete TS-5 + AP-25 rows,
   note the retirement in the same commit.

### P2 — Response-layer edge family — retires TS-1, TS-4, AP-7; closes #166, #116

**Status (2026-07-30, FINAL — Campaign P final physics slice):** TS-1 and
AP-7 retired same-day as originally recorded. **TS-4 is now ALSO
RETIRED** — the oracle follow-up pass
(`docs/research/2026-07-30-ts4-116-oracle-plan.md`) found the freeze the
first implementation attempt hit was one layer downstream of Path 6
(inside `AdjustOffset`'s crease projection against a purely-vertical
offset — a genuine retail-identical degeneracy, not a bug) and ran the
plan's own decisive confirming test: `Ts4SteepRoofWedgeCaptureTests`'s
horizontal-velocity variant (matching the realistic live-play input that
originally validated the shortcut) converges cleanly with the shortcut
removed. The Path-6 steep-poly shortcut is deleted from both
`BSPQuery.cs` and `FlatBspQuery.cs`; the pure-vertical degenerate case is
pinned (not fixed) as register row AD-56. **#116 is narrowed, not
closed**: shape-2 (D4 first-airborne-frame hard-stop) is CLOSED — the
oracle plan's structural dispatch-routing hypothesis was confirmed by
instrumentation with no cdb session needed, and the D4 pin is un-skipped.
Shape-1 (tick-22760 lateral-slide loss) got a real, independently-decomp-
confirmed fix (Path 6's foot-clear/head-hit branch now returns `Collided`
+ `SetCollisionNormal` directly, matching pc:323824-323834/ACE
`BSPTree.cs:221-230`), but the confirming replay showed this does NOT
explain tick-22760 itself — that mover is grounded (dispatches through
Path 5, not Path 6) and the actual "no normal recorded" mechanism
(`SpherePath.PrecipiceSlide`'s `find_crossed_edge`-false fallback) is
independently confirmed byte-exact retail behavior too. The remaining
divergence is most likely this test's simplified door-registration
fixture, not the response layer — see ISSUES.md #116 and the oracle
plan's Addendum 2 for the full trace and the concrete next step (re-run
against the faithful Setup-based door registration). AD-55 (the sled
slope-flatness constant, split out of AP-7's retirement) is ALSO retired
this same slice — byte-proven `cos(10°)` per the oracle plan's Addendum.

The collision *response* layer (what happens after a hit): ground
friction, cliff edges, downhill landings, near-perpendicular wall
slides. One oracle-driven pass; the physics digest's DO-NOT-RETRY table
binds every subagent here.

**Work (research doc FIRST, then port):**
1. **AP-7:** decode the state gate on retail's friction block
   (`calc_friction` region, pseudo-C ~276702-276705) that lets retail
   use threshold 0.25 without hammering normal locomotion (the reverted
   L.3c attempt). Ghidra MCP for the x87 branch if BN is garbled.
2. **TS-1:** port the `EdgeSlide → PrecipiceSlide / CliffSlide` chain
   (precipice context, steep-plane bookkeeping) replacing our
   stop-at-edge.
3. **#166:** port the landing "sled" (Sledding state set/clear sites;
   the sled friction constants already sit in `calc_friction`).
4. **TS-4:** replace the Path-6 steep-poly in-place-slide shortcut with
   retail's `SetCollide → Path-4 → ContactPlane` landing chain, and
   remove the two BSP-layer `SetSlidingNormal` writes (retail's only
   in-transition writer is `validate_transition`).
5. **#116:** the near-perpendicular lateral-slide loss + first-airborne-
   frame divergence, driven by the existing tick-22760 replay and D4
   pins.
6. Apparatus: extend the trajectory-replay tests; capture fixtures
   before changing behavior. Register: delete TS-1/TS-4/AP-7 rows.

### P3 — Remote-object residuals — retires TS-46, TS-23; closes #165; narrows/retires AD-25

1. **TS-46:** pass the Setup's verbatim sphere LIST into the transition
   (`CPhysicsObj::transition 0x00512dc0 → init_sphere`) instead of the
   two-scalar reconstruction, for local player and remotes; derive
   remote step-up/step-down from the Setup instead of the pinned 0.4 m.
   Captured-fixture replays must stay green or be re-baselined with
   evidence.
2. **AD-25:** align the remote post-resolve with the ported
   `handle_all_collisions` (grounded-bounce rule) as the player half
   already did in #182.
3. **#165:** remotes visibly penetrate walls before stopping — diagnose
   against the (now Setup-true) sweep; suspect list starts at the
   catch-up step length vs sweep sub-steps.
4. **TS-23:** parse PlayerKillerStatus from PlayerDescription/property
   updates and plumb PK/PKLite/Impenetrable onto local + remote player
   movers (`OBJECTINFO::init 0x0050cf30` state bits). Non-PK ACE
   behavior must be provably unchanged.

### P4 — World specials — retires AP-71, AP-10

**Status (2026-07-30): COMPLETE**, including a same-day Opus review
fix. AP-71 landed at `d6c3f865` (20 new conformance tests); AP-10 landed at
`cc8d57a2` (12 new conformance tests). Complete solution suite at that gate:
9,946 total across 9 test projects, 9,941 passed, 5 skipped, 0 failed on a
clean run. One run in the same session saw a single unrelated flake
(`AcDream.Content.Tests.Vfx.RetailDatLoaderTests
.AnimationCache_CoalescesSameDidAndAllowsUnrelatedReadsInParallel`, a
parallel-cache-coalescing timing test untouched by either commit) that
passed 3/3 in isolation and on the immediate re-run — full-suite parallel
contention, not a regression (independently fixed afterward at `dc0468cc`).

**P4 review verdict: FIX-FIRST (2026-07-30).** `RestrictionObjPrevalenceInspectionTests`
(`3b5e0992`) measured the installed cell DAT: 103,766 of 729,888 EnvCells
across 1,293 landblocks — the entire housing estate, `restrictionObj` GUIDs
`0x70xxxxxx` — carry a baked `RestrictionObj`. AP-71's fail-closed default
(landed with `CanMoveInto` deliberately unmodeled, per the original AP-129
row) would have locked every apartment/cottage/villa interior for every
player, including its own owner — a live regression, not the "inert in dev
content" the row assumed. Fixed at `7a0f836a`: `ACCWeenieObject::CanMoveInto`
(0x0058da40) and `RestrictionDB::IsAllowedIn` (0x005ae8f0) are now ported
verbatim, fed end-to-end from CreateObject's HouseOwner/HouseRestrictions/
Monarch PWD-tail fields (previously parsed-and-discarded) plus a new live
`House_UpdateRestrictions (0x0248)` parser, and resolved through a new
`PhysicsEngine.Objects` property wired to the canonical `ClientObjectTable`
in `RuntimeEntityObjectLifetime` (production fix, not just gate logic — an
unwired table still fails closed). AP-129 is narrowed (not retired) to the
genuine residual: no sequence-based staleness rejection for
`House_UpdateRestrictions` (low-probability, self-correcting), and the
outdoor `CLandCell` restriction path (a separate DAT structure) remains
unported, unaffected by this fix. Gate: `AcDream.Core.Tests` 4,049 passed / 2
skipped / 0 failed; `AcDream.Core.Net.Tests` 761 passed / 0 skipped / 0
failed; complete solution suite 9,961 total, 9,956 passed, 5 skipped, 0
failed.

1. **AP-71:** port the `CObjCell::check_entry_restrictions` gate at the
   head of `find_env_collisions` (pc:309576) — barred house cells block
   at the threshold client-side. Landed: the gate is wired at the top of
   the indoor branch of `Transition.FindEnvCollisions`; `CellPhysics
   .RestrictionObj` is fed from the DAT-baked `EnvCell.RestrictionObj`
   field (§4.3's open question resolved via ACE's DatLoader + an
   independent `Chorizite.DatReaderWriter` reflection probe — it's a
   plain per-cell DAT field, not a live wire override) in both the dev
   and production caching paths, at zero bake-format cost. The mover's
   `CanBypassMoveRestrictions` (BF_ADMIN & BF_IMMUNE_CELL_RESTRICTIONS)
   is decoded via the TS-23 PWD-bitfield pipeline. The original landing
   deliberately left `CanMoveInto` unmodeled (fail-closed default, filed
   as AP-129) — the P4 review found this fails closed for the ENTIRE
   housing estate and required the fix-first pass described above.
2. **AP-10:** restore retail's 0.1 m water sink-in; while there, verify
   the water-contact step behavior (`WATER_CONTACT_TS` consumers)
   against retail and file anything found. Landed: the dry-corner
   constant is restored (full suite green — the sticky Contact/OnWalkable
   bit argument held); `WaterContact` is now produced at every
   `Contact`/`OnWalkable` commit site. No confirmed retail consumer of
   `WATER_CONTACT_TS` was found this pass; filed as #264 along with two
   other explicitly-unverified water items (the `ENTIRELY_WATER`
   ethereal/swim terrain-collision exemption, and jump/swim
   movement-effects) — none block this port.

**P4 review addendum (2026-07-30): APPROVED after one FIX-FIRST round.**
The initial AP-71 landing failed closed with `CanMoveInto` unmodeled; the
prevalence inspection (`3b5e0992`) proved that locks all 103,766 housing
EnvCells. `7a0f836a` ports `CanMoveInto`/`IsAllowedIn` verbatim
(owner/self/null-db admit; unresolved object blocks), captures the
previously-discarded HouseOwner/Monarch PWD fields, parses
`House_UpdateRestrictions 0x0248` live, and wires the canonical object
table into the gate. AP-129 narrowed to the sequence-byte and outdoor
RestrictionTables residuals. Suite 9,956/0/5.

### P5 — Deferred fidelity — closes #167, #153, #72

**Status (2026-07-30): item 1 (#167) COMPLETE.** Both blockers resolved
without Ghidra/cdb — the two x87-elided constants were byte-decoded
straight from the matching binary's raw machine code
(`docs/research/2026-07-30-constraint-leash-constants.md`). The leash is
now armed at every current acdream inbound-position acceptance seam
(`ConstraintDistance`, `LiveEntityNetworkUpdateController`,
`PlayerMovementController.SetPosition`/`BlipPosition`), the per-tick
`PhysicsBody.IsFullyConstrained` push replaces the always-false stub, and
register row TS-35 is deleted. Full Core/Runtime/App suites pass with new
conformance tests (leash-armed jump refusal, teleport-vs-blip
anchor/teardown, taper reduction, remote-tick push). Items 2 (#153) and 3
(#72) remain open.

1. **#167:** decode the two unknown x87 ConstraintManager constants
   (Ghidra) and port leash arming.
2. **#153:** the far-teleport arrival onto an unstreamed landblock near
   a 192 m edge — apparatus first (the issue's own trigger table), then
   the streaming-gap hold shape ALREADY sketched there (freeze the
   per-tick resolve until the landblock loads — the async equivalent of
   retail's synchronous load; this is an AD row, not a workaround, and
   gets filed as one).
3. **#72:** close on the R6 evidence (DAT-authored omega ±1.5 rad/s is
   live; the cdb confirmation ask is obsolete).

### P6 — #262 login run-on-the-spot (live defect)

Probe-instrumented fresh-process login repros (`ACDREAM_PROBE_RESOLVE=1`
+ net probes) against local ACE; the issue's hypothesis list is the
script. Root cause, fix, regression test. No workarounds (no auto-recall,
no synthetic position kick). Runs serialized (owns the build tree +
client).

### P7 — Ledger + camera feel

1. Retire the stale TS-25 row (outbound stance ships via
   `RawState.CurrentStyle` since #219) and refresh TS-24/TS-35/TS-40
   classifications.
2. #115 camera-drag: investigation-only against `CameraManager`
   constants (AD-37's vector-nlerp vs retail quaternion-slerp is the
   prime suspect); fix if a concrete divergence falls out, otherwise
   re-classify with evidence.
3. Reconcile #172/#173/#174/#175/#41 statuses via the final matrix.

---

## Implementation-phase closeout (2026-07-30) — awaiting the matrix

Every implementation slice is COMPLETE and Opus-reviewed; the campaign now
waits on the single user gate below.

**Register scorecard:** goal-enumerated physics stopgaps at ZERO — TS-1,
TS-4 (+ its FlatBspQuery twin), TS-5, TS-23, TS-35, TS-46 retired by
ports; TS-25 retired on #219 evidence; TS-24→AD-57, TS-40→AD-58
re-argued. AP-7, AP-10, AP-25, AP-71 retired; UN-8 and AD-55 retired by
raw-byte proof; AD-25 retired. AP-127 was subsequently retired by #268;
the remaining new argued rows are AP-128/129,
AD-53/54/55(retired)/56/57/58.

**Issues:** #72, #153, #167, #255 closed; #116 shape-2 closed /shape-1
narrowed to a probable harness artifact (response layer byte-verified);
#165 diagnosed to the render-lag candidate (matrix scenario 8a decides);
#166 all four composite deviations landed (scenario 5 decides); #262
apparatus permanently live + 3/3 clean probe logins (scenario 11
decides). Notable finds along the way: ACE's inverted leash-start
mapping, ACE's radians/degrees sled-constant bug (cos 10°), the
housing-lockout prevalence catch (103,766 restricted cells), and the
HouseOwner/Monarch PWD fields that were parsed-and-discarded.

**Verification:** every slice gated on the complete Release suite; final
state 9,977 passed / 0 failed / 4 skipped (the D4 un-skip retired one
permanent skip). Suite grew from 8,826 to 9,977 tests over the campaign
(+1,151, all conformance/golden/pin coverage).

## Final batched connected visual matrix (the ONE user gate)

1. Burden >100%: run slows, jump shrinks; ~200%: barely moves/jumps.
2. Repeated jumps drain stamina; low stamina → weak/refused jump;
   exhaustion behavior matches retail.
3. Fresh vitae: movement penalty present.
4. Walk off a cliff/roof edge: slides over like retail, no dead stop.
5. Downhill jump landing: sled glide + bounce.
6. Shallow-angle wall graze: lateral slide preserved.
7. Packed crowd: spacing + shuffle-out unchanged (regression).
8. Two-client: remote stops at walls without visible penetration;
   remote ceiling-jump bounces down immediately (#173); Holtburg portal
   platform step-up (#172); door Use after jumping (#174); closed-door
   collision matches the visual door (#175); observed-player blips
   gone (#41).
9. Locked/barred house: blocked at the threshold.
10. Wading: slight retail sink-in.
11. ~20 fresh logins: no run-on-the-spot.
12. Regression sweep: walk/run/strafe/turn/jump/stairs/doors/water
    edges feel unchanged from the accepted R6 baseline.

## Risk notes

- P2 and P3 touch the frozen-adjacent transition internals — every
  subagent prompt must carry the digest's DO-NOT-RETRY table and the
  no-workarounds rule; 3 failed attempts on any item = stop and build
  apparatus, per [[feedback_apparatus_for_physics_bugs]].
- TS-46 changes the collision capsule of every mover; the captured
  replay fixtures pin behavior — re-baseline only with a recorded
  retail argument.
- P1's enchantment-aware skill read is the scope-creep risk; it is
  bounded to the run/jump query path by this plan.

## Live-gate session 2 (2026-07-30) — speed + bounce family landed

The matrix's first live rows surfaced three defects; all three are
root-caused, retail-ported, and user-accepted in the same session:

- **#266 CLOSED** — run speed: retail `MovementSystem::GetRunRate`
  (0x006b0950) treats 800 as an EXACT-EQUALITY sentinel; ACE's `>= 800`
  reading is a misread of the same x87 mush that our P1 port inherited,
  flat-lining every maxed character at 4.5 (retail-true ~3.70, +21%,
  vitae-independent). Byte-decoded, fixed at `61e95916`; the [stat-chain]
  live capture proved the vitae→skill chain correct end-to-end. Side-by-
  side pace vs a retail client accepted by the user.
- **#265/#166 landing-momentum + bounce family** — two stacked fixes:
  (1) `c60f6e5d` stopped hand-zeroing grounded residual velocity and
  wired the never-written `GroundNormal` (roof slides restored);
  (2) `2d611b2b` replaced the AD-25 landing adaptation with the retail
  mechanism: `check_contact` (0x0050f5b0) transition seeding, the
  velocity-free `SetPositionInternal` commit (0x00515330), and the live
  5%-elasticity landing reflect (DEFAULT_ELASTICITY 0.05 @0x007c6a7c).
  Downhill bounce chain, flat-ground pop, and clean uphill landings all
  user-accepted ("almost pass with merits"). Investigation + byte-decode
  record: `docs/research/2026-07-30-landing-bounce-family.md`.
- **#267 shipped** (vitae/buff panel values; attributes vitae-immune).
  **#268 closed 2026-07-31**: the complete
  augmentation chain is shared by panel and Runtime movement; AP-127 is
  retired. Attributes, secondary attributes, and skills use retail's
  vitae-excluded green/red comparison. The selected-skill footer now renders
  per-fragment colors through the shared retained text primitive, using the
  authored 0x1B palette exactly: #7FFFFF vitae, #00FF00 buff, #FF0000
  debuff. TS-8 is also retired: a real live 0x02C2 payload carries its full
  StatMod through dispatch and changes the effective skill immediately. The
  user accepted the live colors, values, footer, and immediate row refresh.
- **#269 closed 2026-07-31** — the live 2,184-quantum trace proved the
  landing reflect and friction math were correct. ACDream omitted retail's
  `OBJECTINFO::kill_velocity` before restoring a remembered contact plane
  in `CTransition::validate_transition @ 0x0050AA70`, retaining full
  downhill velocity while repeatedly re-grounding the mover. The exact
  non-OK-only restore/kill order and final last-known validity overwrite
  are now ported, focused/full gates pass, and the user accepted repeated
  slope jumps. Evidence:
  `docs/research/2026-07-31-269-slope-stop-capture.md`.
- **#271 closed 2026-07-31** — a bounded stair-side
  trace proved ACDream could bypass retail's current-position edge back-probe
  by promoting a stale `LastWalkable` tread. That made PrecipiceSlide reverse
  an uphill tangent and rapidly carry the player down the stairs. The two
  stale-history substitutions are removed; current-walkable, back-probe, and
  no-walkable outcomes now follow `CTransition::edge_slide @ 0x0050B3D0`.
  The exact captured frame is pinned in the existing installed-stair fixture
  and the complete Release suite passes 10,062 tests / 5 skips. The user
  accepted repeated uphill runs while pressing into the stair sides. Evidence:
  `docs/research/2026-07-31-271-stair-side-slide-capture.md`.
- **#272 complete and user-accepted 2026-07-31** —
  `CACQualities::InqLoad` consumes enchantment-adjusted Strength through
  `InqAttribute`, but Runtime movement and both retained burden displays read
  raw Strength and did not share the enchantment invalidation edge. They now
  consume `GetEffectiveAttribute(Strength)` and
  `Spellbook.EnchantmentsChanged`, so buff, dispel, expiration, and death
  purge recompute the same burden state immediately. Focused and full
  Runtime/App tests pass.

Matrix rows accepted so far: speed parity, roof slide, downhill bounce,
flat pop, uphill landing, and #269's slope-stop feel
(rows 3/4/5-partial/12-partial). Remaining rows: 1, 2, 6, 7, 8, 9, 10,
and 11. The #269 checkpoint passes 4,107 Core tests / 2 skips and 439
Runtime tests / 0 skips; the complete Release suite passes 10,061 tests /
5 skips / 0 failures.