GridLab creates logic puzzles to be solved by hand, on paper, on a wooden Sudoku board, on an e-ink reader or on iPad with Apple Pencil. It is not a game and does not try to be one: it gives no hints, keeps no score and never asks you to come back every day. It prepares the puzzles and then steps aside. It works on iPad and on Mac, and the library syncs through iCloud, so a puzzle created on one device is there on the other. ▸ FOUR PUZZLE TYPES Sudoku is free, in full and for good, with four variants that can be combined: X-Sudoku with its two diagonals, Anti-King, Anti-Knight and Hyper with its four extra boxes. Kakuro and Binary unlock with a single purchase, and Hashi comes as a gift. Kakuro is made of cross sums on 9×9 and 11×9 grids, Hashi asks you to connect numbered islands with bridges on grids from 9 to 15, and Binary fills grids from 10 to 14 with balanced zeros and ones, also with the = and ≠ signs variant. The rules of all three can be read in the glossary before you buy them. ▸ ONE SOLUTION, ALWAYS Before saving a puzzle GridLab checks that it has exactly one solution and discards those that have two. Every puzzle can be solved by deduction, without guessing. ▸ DIFFICULTY Each type has four levels, from Base to Expert, and each sets them with its own levers: the given digits in Sudoku, the length of the runs in Kakuro, the number of islands and of reasoning steps in Hashi. On Sudoku and Binary, logical depth from 1 to 5 fine-tunes how sparse a puzzle is within its level. ▸ IN BATCHES Set the parameters once and choose how many puzzles you want, up to 20 at a time on iPad and 50 on Mac. Each one goes into the library as soon as it is ready, so an interruption never costs you the ones already made. ▸ PDF AND EPUB COLLECTIONS Pick puzzles from the library and turn them into a book with your own title and author, an index that takes you straight to each puzzle, a page with the rules of the types it contains and, if you want, the solutions at the end, apart from the puzzles. You choose the order, for example from easiest to hardest. The PDF has one grid per page with room to write, and the ePub is made for e-ink readers such as Kobo. A single puzzle can also be exported as PNG, to print it on the spot, and as SVG, for laser cutting and wood engraving. ▸ NO DISTRACTIONS No ads, no subscriptions, no tracking and no notifications: GridLab collects no data. If you find it useful you can support its development with a voluntary contribution from the Support section, where you will also find the address to write to us.
Productivity · iPhone, iPad · Free
