GridLab

GridLab is now on Mac too. With batch generation you set the parameters once and find twenty puzzles ready in your library.

GridLab creates Sudoku puzzles designed to be solved by hand. On paper. On wood. On e-ink.

It's not a game. It doesn't teach, hint, or guide. It prepares puzzles, then steps aside.

Available on iPad and on Mac, with the library synced through iCloud.

▸ ADVANCED VARIANTS

Each puzzle freely combines one or more geometric constraints:

• Classic: the standard rules • X-Sudoku: both main diagonals must also contain 1-9 • Anti-King: no equal numbers in diagonally adjacent cells • Anti-Knight: no equal numbers at a chess knight's move distance • Hyper Sudoku: four additional 3×3 boxes overlaid on the grid

Constraints combine freely: a puzzle can be X-Sudoku and Anti-Knight at the same time.

▸ UNIQUENESS GUARANTEED

GridLab mathematically verifies that every puzzle has exactly one solution before finalizing it. No ambiguity, no flawed designs.

▸ DIFFICULTY AND DEPTH

Two parameters shape a puzzle, and both stay recorded on it:

• Difficulty: how many cells are removed, from Base to Expert • Logical depth: how many consecutive deductive steps are needed before a safe placement appears, from 1 to 5

Every additional variant shrinks the space of valid grids, so the real difficulty rises even with the same parameters.

▸ BATCH GENERATION

Set the parameters once and choose how many puzzles you want. Each one is saved to the library as soon as it is ready, so an interruption never costs you the ones already made. Up to 20 puzzles at a time on iPad, 50 on Mac.

▸ EXPORT

• PDF: collection of diagrams, usable with Apple Pencil on iPad • PNG: for quick printing or replication on physical materials • SVG: for laser cutting, wood engraving, craft applications • ePub: puzzle collections for e-ink devices

With "Include solutions": solutions are appended at the end of the document, separated by a title page, for personal review after solving.

▸ VERIFICATION

After solving on paper, enter your result in the app for a direct comparison. No guided explanation. Just: valid or invalid.

▸ NO GAMIFICATION

No points. No levels. No badges. No notifications. No ads. No subscriptions.

GridLab is built for those who want to work with their mind. Not for passive entertainment.

▸ BUILT-IN GLOSSARY

The Glossary section explains each variant with mini-grids that highlight the constraints, and documents difficulty, logical depth and the uniqueness guarantee.

▸ SUPPORT THE PROJECT

GridLab is free and collects no data. If you find value in the app, you can support development with a one-time voluntary purchase from the "Support" section.