v0 state

gridSize

// 4x4

numPairs

faces

faces are the 8 distinct emoji; each appears exactly twice on the board.

tile

tile holds the face index (0..7) for a cell and whether it is matched.

board

board is the full game state. It is a package-level singleton so the realm persists a single shared game.

shuffle

shuffle produces a deterministic permutation of the 16 tile faces from a 64-bit seed. It fills a slice with two of each face index then applies a Fisher-Yates shuffle driven by a simple LCG — fully deterministic, no RNG.

ensureStarted

reset

NewGame

NewGame reshuffles the board using the current block height as the seed.

Flip

Flip reveals the tile at index (0..15). Rules: - If two tiles are already showing from a previous unmatched attempt, this Flip first clears them (they turn back to hidden), then reveals the requested tile as the first of a new attempt. - Revealing the second tile of an attempt completes a move: matching faces stay face-up (matched); a mismatch leaves both showing until the next Flip clears them. - Flipping an already-matched or already-showing tile is rejected.

solved

cellFace

cellFace returns the emoji to display for a cell given the current state.

Render

Render draws the board as Markdown: a 4x4 grid, move count and solved state.