puzz.

What this is

puzz is the puzzle wing of an experiment running across this repo: take a vast combinatorial space, generate it deterministically from a seed, and put an interestingness engine on top to decide which points are worth a second look. The atlas of worlds at mappa does it for planets; the Ludographer does it for board games. Here the domain is logic puzzles — and the interestingness engine is something special: a real solver.

Why a solver is the right oracle

For most generated artifacts, "is this interesting?" is a matter of taste you approximate with a hand-tuned battery or a learned critic. A logic puzzle is different. There is a precise, checkable notion of a good one:

• It has exactly one solution. The generator proves this by exhaustive bounded search — a puzzle ships only when the solver counts exactly one solution.
• It is fair. The clues can be reached by pure deduction, with no guessing. The generator carves clues only while a no-backtracking propagation engine can still finish the grid.
• Its difficulty is earned, not asserted. The same engine records which reasoning techniques the solution forces, and how long the chain runs. The difficulty score is read off that trace.

So the solver does triple duty: it certifies, it grades, and — ranking seeds by a small battery of aesthetic signals built from the trace — it curates. Every number on the page line is a puzzle no human authored; the solver vouched for each one.

The genera

Two puzzle types share a single boolean-cell deduction engine:

Binairo

A square grid in two colors. No three of a color in a row; each line balanced; no two lines alike. The engine deduces with three named techniques — no-triple, line balance, unique lines — and the grade reflects which a given puzzle needs.

Nonogram

Row and column run-length clues reconstruct a hidden picture. The engine is a real nonogram line-solver; it distinguishes free overlap (a long run forced to overlap itself) from cross-chaining (a cell known from one line constraining the crossing one).

The space is built to grow

The interesting claim isn't the count of puzzle types — it's that one solver certifies, grades, and ranks every instance, turning a combinatorial space into an atlas you navigate by interestingness. Adding a genus — Star Battle, Slitherlink, Akari — is one module implementing the same contract: a propagator with a complete validity check, a seeded generator, and a technique-tier table. Those harder genera will populate the upper difficulty tiers these two gentle ones leave open.

Determinism

Page number n yields the identical puzzle on every machine, for ever (seeded xmur3 → mulberry32, the repo's standard pair). That's what makes /puzz/?n=42 a permalink rather than a fresh roll.