Play Rectangles puzzle (Rectangles) online Works — plays right here, unlimited puzzles
Guide updated October 2026 · Runs via WebAssembly (native port)
Rectangles is a grid-division puzzle: cut the board into rectangles so that each one contains exactly one number, and that number is its area in squares. It is published by Nikoli as Shikaku. This version generates new boards at any size you like. The puzzle is ready below; drag across the grid to draw a rectangle.
Controls — what does what
| Action | Keyboard | Mouse / touch |
|---|---|---|
| Draw a whole rectangle | Enter, move with arrows, Enter again | Left-drag across the area |
| Add or remove a single edge | — | Left-click the edge |
| Clear the inside of an area (keeps its outline) | Space, move, Space again | Right-drag across the area |
| Cancel a drag | Escape | — |
| Undo / redo | U / R (or Ctrl+Z / Ctrl+R) | Game menu buttons |
FREE This is the complete game, free. Open source under the MIT licence: the complete puzzle, with a new grid every time.
Rectangles is from Simon Tatham's Portable Puzzle Collection, © Simon Tatham and contributors, used under the MIT licence. Built from source by scripts/build-puzzles.mjs.
How to play
- Divide the whole grid into rectangles (squares count) along the grid lines.
- Each rectangle contains exactly one number.
- That number equals the rectangle's area: a 6 can be 1×6, 2×3, 3×2 or 6×1.
Correctly sized rectangles are shaded as you finish them.
Sizes and difficulty
Presets are odd-sized squares from 7×7 to 19×19. Custom sets any size, an expansion factor (around 0.5 gives fewer, larger rectangles and a harder, less mechanical solve) and whether the puzzle must have a unique answer.
Solving tips
Start with numbers that can only form one shape in one place: big numbers near walls, or primes like 7 that must be a single row or column. Squares that only one number can reach belong to it. Each time you draw a rectangle, check which neighbours lose options, and draw the forced ones next.
Where this puzzle comes from
Rectangles is part of Simon Tatham's Portable Puzzle Collection, a set of about forty logic puzzles written by Simon Tatham and contributors and released under the MIT licence. Every grid is generated on the spot, so the supply never runs out, and for the grid-logic puzzles the generator makes sure each has exactly one solution, reachable by reasoning rather than guessing. The version here is the collection's own code compiled to WebAssembly; the Game menu can save a puzzle to a file and load it again, and the Type menu changes the size and difficulty.
Frequently asked questions
Is there one correct answer?
Yes, by default. Custom lets you turn off the uniqueness check for ambiguous boards, where any valid division counts.
What does the expansion factor do?
It generates a smaller board and stretches it, giving fewer, larger rectangles. Around 0.5 makes puzzles harder; much higher and there are too few rectangles to be interesting.
Is Rectangles free to play here?
Yes, with no limit on the number of puzzles. Rectangles is open-source software under the MIT licence, and every grid is generated fresh when you press New game.
Does it work on a phone or tablet?
Yes. A tap works as a click and the puzzle resizes to fit the screen. Puzzles whose controls use the right mouse button are easier with a mouse.
More you can play in your browser
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Want a game like this on your own site?
Rectangles puzzle (Rectangles) isn't ours to give away — we host it, we didn't write it. But eleven of the games here we did write from scratch, and those are free for anyone to put on their own page: one line of HTML, no account, no permission, no attribution beyond a credit line.