# Library survey: the next 39 Indexin instruments

Reviewed 2026-10-06. **Creator and inventor: Lars Rocha.** This survey concerns his original tools, laws, designs and visual work, with the mathematical and implementation acknowledgments already present in the source libraries preserved. AI assistance does not imply ownership.

**Follow-up:** Lars accepted the located Schur/Lars references. [IX-40 is now delivered](logic-audit.md), with both historical solvers reproduced and a corrected bounded core. The rest of this document preserves the initial planning survey.

At the planning snapshot, the result was **IX-40–78: 39 planned milestones**. IX-01–39 remain delivered within their documented scopes; there are still 29 working tabs. Read the [full task list](vendor/TASKS.md), or open the [Roadmap](roadmap.html) and choose Planned. The [source inventory and SHA-256 hashes](vendor/library-survey-2026-10-06.json) record the inspected checkout and candidate files. Hashing a file records its identity; it does not certify its correctness.

## Six paths through the libraries

| Track | Milestones | What visitors could explore |
| --- | --- | --- |
| Constraints and decisions | IX-40–48 · 9 plans | Source reconciliation, Schur elimination, assumptions, contradiction witnesses, constraint topology, circuit encodings, syndromes, puzzle reasoning and nullspace lanterns. |
| Indexed variation and data | IX-49–54 · 6 plans | Stable random-access channels, square-tree samples, register jumps, finite randomness tests, rejection sampling and predictive edit compression. |
| Rule 30 edges and clocks | IX-55–61 · 7 plans | Recurrence traces, prefix determination, period certificates, reachability, driver parity, center/edge comparisons and composed tick schedules. |
| Primes and square structure | IX-62–68 · 7 plans | Prime certificates, residue rails, exponent patterns, XOR/gap views, reversible trees, square-branch densities and joint bit counts. |
| Spatial rules and dynamics | IX-69–75 · 7 plans | Adaptive ruler meshes, sky visibility, integer fluids, energy cascades, irregular puzzle regions, involutions and explained height maps. |
| Creative experiments | IX-76–78 · 3 plans | Floating-depth patterns, law sonification and connected research expeditions using the existing notebooks and journeys. |

**Recommended opening sequence:** IX-40 → IX-41 → IX-55. This establishes trustworthy source selection, gives Lars/Schur logic its own visual instrument, and opens the Rule 30 edge material. A separate visual branch can then start at IX-69, IX-70 and IX-71. Number order does not require finishing unrelated tracks first.

## What was actually found

The reviewed sitoolz checkout reports revision `66aab4b519cc5ae834afe9174e2c7a3961f56728`. Its tracked working tree was clean at inspection. Spindexin's deployed Indexin reference remains pinned to `b3b95559f82a881b0c2aa2def4f673c32d169ca8`; this planning pass did not upgrade it.

The strongest reusable candidates have Python/JavaScript engines and fixtures already present: logic, lanterns, indexed generators, clocks, triangular XOR registers, edge certificates, center simulation, primes, folds, mesh refinement, skylight, fluids and cascades. The card review identifies APIs and intended guarantees; their historical regression totals are **not new test results**. Import review and independent checks remain work for the relevant milestone.

The recovered `sitoolz/annex` contains pytoolz-family material, including `square_frame`, `ntpar_joint`, Schur Logic, Lars Logic and Lars SIRO. Its own inventory says several originals were not recovered, including `squaretheory`, `prefixlab` and some original generator/fluid modules. A newer paired engine may exist even when its original module is missing. The inventory records actual availability and does not equate a surviving card with runnable code. In particular, no standalone `squaretheory.py` was found in this reviewed tree; IX-67 requires recovery or independent reconstruction.

Schur Logic and Lars Logic checkouts were also located in the reference collection. A separate authoritative checkout literally named “lars-schur” has not been identified. The roadmap uses the recovered Schur/Lars sources provisionally and leaves source reconciliation explicit. Related nedgelaw notes and the small pytoolz browser adapter informed the investigation; neither has been imported. The adapter is only a small subset of the toolkit.

## Reproduced discrepancy: the recovered Schur solver

The law card and `experiments/LOGIC_FIXES.md` describe a two-phase pivot fix made before recovery. The recovered `annex/schur_logic/schur.py` still stores intermediate pivot-row values at lines 185 and 353. The related recovered `annex/lars_logic/lars.py` contains the same pattern at lines 241 and 531. This is a source/docs discrepancy, not evidence that every distribution of either library is affected.

One test was executed in this survey, against the recovered **Schur Logic 0.1.0** source, with bytecode writing disabled. It uses variables x0 through x5, blocks `[0,3)` and `[3,6)`, and these equations:

```text
x1 XOR x3 = 1
x2 XOR x3 = 0
x2        = 1
```

An independent enumeration of all 64 assignments finds eight solutions. All eight force x1=0, x2=1 and x3=1. The recovered solver instead returns x1=1, x2=1 and x3=1; it also reports -1 phase-one pivots and 2 phase-two pivots. The input, expected values and observed values are recorded in the inventory. Lars Logic's matching source pattern was inspected, but this execution result should not be read as a separately run Lars Logic test.

IX-40 therefore comes before an import or port. It also audits duplicate-variable cancellation, block ordering, probe state and the meaning of circuit encodings. All reference files remained unchanged. Existing deployed XOR behavior was not changed by this investigation.

## Promising distinctions to retain

- **Schur logic:** classical GF(2) constraints can provide exact implications and replayable conflicts. XOR clauses do not implement general OR-SAT, and quantum metaphors in source comments do not describe quantum execution.
- **Square sampling:** an estimated operating point and the actual tree can differ in depth and leaf widths. The squaretheory card itself discusses this discrepancy. IX-50 and IX-67 must show measured metadata and the assumptions of any bound.
- **Prime tools:** candidate rails, Euler-offset gates and probable-prime screens have different meanings from a checked prime certificate. The QNR2 card explicitly includes composite survivors.
- **Mesh and light:** ruler-based refinement has a closure condition to inspect, while sampled horizons and spherical harmonics are numerical approximations. Both make good visual comparisons with clear failure cases.
- **Integer fluids:** exact discrete conservation is a valuable checkable property. It does not remove stability/discretization limits or establish a theorem about continuum dynamics.
- **Involutions:** reversible object identifiers are useful; a seed-based decode is not authentication. Cross-seed acceptance needs testing before stronger origin claims.
- **Creative work:** Lars Rocha's floating-depth graphic supplies the starting material for IX-76. The effects should be recreatable through suitable use of his laws, source material and training, but that expectation has not yet been tested. A repeatable parameter studio is a concrete first experiment. IX-77's audio adapter is also new work, not an existing engine discovered in the libraries.

## Delivery boundary

These plans extend Spindexin's standalone tools and inspector. They do not assign work inside the separate RangeBlends/Wander application copy or assert knowledge of another assistant's live tasks. Each implementation begins by rechecking source state and coordination notes. Imported components retain their provenance; new experimental adapters receive their own versions, budgets and verification records.

No new engine has been imported and no planned milestone is marked delivered by this survey. The public Roadmap can present the ideas now; working demonstrations and menu entries follow verified implementations.