# Plyquarry > A rules sandbox for inventing two-player abstract strategy games (perfect information, no luck). Build a ruleset from > controls, play it on the board, auto-play it engine against engine, then ask a model to critique the balance with > concrete rule changes, or to write a printable rules card. https://plyquarry.skillsafe.ai/ Built on the skill @jwynia/abstract-strategy (https://skillsafe.ai/skill/@jwynia/abstract-strategy) by jwynia: designing abstract strategy games with perfect information, no randomness and strategic depth, and evaluating balance. ## Who it is for Hobby game designers, teachers inventing classroom games, families making up a game for the holidays. ## What runs free in the browser - Rule controls: square or hex (rhombus) board 4x4 to 10x10; up to three piece types drawn on a 5x5 move stencil (inner ring = step/slide directions with a range, outer ring = leaps over anything); setup (empty, home rows, alternate cells); phase (move only, place only, place then move, with a reserve); capture (replacement, jump-over chains of up to 8 jumps, custodial trapping, forced capture); win conditions (connect N in a row, reach the far row, capture all, majority at a full board, immobilise); actions per turn, first-turn actions, extra reserve for the second player; a ply limit ending in a draw or a majority count. Lint warnings for impossible or dead rules. - A live board: legal moves shown when a piece is selected, hand play for both sides with undo, or play against a random, greedy (one ply) or minimax (two ply, beam-limited) engine. - Auto-play: seeded, bounded (400 games, 60 with minimax, 400 plies each), run in short slices with progress. Reports first-player (ink) win rate, second-player win rate, draw rate, the first-player edge, average and median length, a length histogram, which win condition decided each game, captures per game and moves per position. After a rule change, each headline number shows what it was on the previous auto-play. - Six presets rebuilt from classic public-domain abstracts and named generically: Five Stones, Far Row Race, Diagonal Jumpers, Sandwich, Place and Shift, Hex Lines. Three carry free example replies for both asks. - Exports: ruleset JSON (opens again), rules card as Markdown and a print stylesheet, simulation CSV, board SVG, and a link that carries the ruleset in its #fragment so anyone who opens it gets the same rules on the board. - History: one record per ruleset with its last simulation, in the signed-in user's account (collection `rulesets`), mirrored in the browser. ## The two metered asks (model gpt-terra) Input (all strings): `task` (`critique` | `sheet`), `ruleset` (JSON), `summary` (JSON simulation summary; an empty string on a `sheet` ask made before any auto-play), `lint`, `fields` (the only fields a change may target, with legal values), `previous` (earlier summary and accepted changes, for a re-critique), `designer_note`, `clipped`. The model never sees moves or game trees. - `critique` returns a verdict (promising, lopsided, drawish, degenerate, too-short, too-long, broken), a headline, findings each tied to a summary statistic with its exact value, rule changes as field -> value with a one-line reason, what to watch after re-simulating, and on a re-critique what moved since the last round. - `sheet` returns a rules card: components, setup, turn, each piece's moves, capture, winning (one entry per enabled win condition), ending, tips and a stats line. The browser reconciles every reply: cited rates must match the summary within 0.03, lengths within 5%, every change must name a catalogue field with a legal, different value, and a rules card must cover exactly the ruleset's pieces and win conditions. Accepted changes apply to the controls; one click re-simulates; the next critique compares. ## Links - App: https://plyquarry.skillsafe.ai/ - API tutorial: https://plyquarry.skillsafe.ai/api.html