Rain Grid Puzzle

A real city's sunrise builds a fresh board every day. Seventy-two handcrafted lattices, no ads, no account, and every puzzle verified solvable before you see it.

Tap a tile and it flips — along with its four neighbours. That single rule is the whole game. Everything after it is consequence.

Blue Grid Puzzle is a lights-out puzzler played on an 8x8 lattice of glowing blue tiles. Every board asks you to bring the lattice to one shade — all dark, or all lit — inside a fixed budget of taps. Match the shortest known route and you earn three marks. Waste taps and you run the budget dry.

SEVENTY-TWO BOARDS, SIX CHAPTERS Each chapter introduces one idea, then leans on it hard. • First Light — plain tiles and generous budgets, to learn how a tap ripples • Ignition — the target flips; light the whole lattice instead of shutting it down • Anchorage — anchor tiles are welded shut and never move • Beamline — beam tiles sweep an entire row instead of a cross • Driftfield — drift tiles dim themselves one turn after you light them • Convergence — every mechanic at once, on the most awkward shapes in the game

Twenty cut-out lattice shapes — rings, spirals, hourglasses, gateways, staircases — change how far a tap can travel.

A NEW CITY EVERY DAY The Daylight Dispatch picks one of forty real cities each day and fetches its actual sunrise, sunset and daylight length. Those numbers build the board: long days become light-up puzzles, short days become shut-down puzzles, and an overcast reading welds more anchors into the grid. Solve it to extend your streak. Readings are cached, so yesterday's list stays readable with no signal.

BUILT TO BE FAIR Every board is generated on your device and verified solvable before it is handed to you. A built-in solver computes par for each layout, so the three-mark target is always genuinely reachable — never a guess. Stuck? Spend a beacon on a hint that highlights the next tap along a shortest route from wherever you are.

QUIET BY DESIGN No ads. No account. No analytics. No tracking of any kind. Your progress lives on this device and nowhere else. The only network request the app ever makes fetches public sunrise times for a city from a fixed list that ships inside the app — your own location is never requested, read or sent.

ALSO INSIDE • 26 achievements across solving, precision, streaks, mechanics and exploration • Five unlockable lattice palettes, earned with marks • Portrait and landscape on both iPhone and iPad • Full VoiceOver, Dynamic Type, contrast and Reduce Motion support • A calm-animation switch, plus independent sound, music and haptics toggles • Put your own photo behind the lattice using the camera or your library • Plays completely offline — only the daily reading needs a connection