Play Untangle (planar graph puzzle) (Untangle) online Works — plays right here, unlimited puzzles
Guide updated October 2026 · Runs via WebAssembly (native port)
Untangle is a geometry puzzle: you are given dots joined by straight lines that cross all over each other, and you drag the dots around until no two lines cross. Every puzzle is guaranteed to be solvable. The idea comes from John Tantalo's Flash game Planarity. The puzzle is ready below; drag any point to start.
Controls — what does what
| Action | Keyboard | Mouse / touch |
|---|---|---|
| Move a point | Arrow keys to choose, Enter to pick up and drop | Drag it |
| Cycle through points | Tab or Space | — |
| 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.
Untangle 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
- Points can be moved anywhere; lines stay attached to their points.
- The puzzle is solved when no line crosses any other line.
Sizes and difficulty
Presets have 6, 10, 15, 20 and 25 points. Custom accepts any number of points; difficulty rises quickly with the count.
Solving tips
Find a triangle or other small cycle and spread it out large, then pull its neighbours into the right faces. Move points with few connections out of the way first; they rarely cause trouble. Work outwards from a tidy region rather than trying to fix the whole tangle at once.
Where this puzzle comes from
Untangle 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 every puzzle solvable?
Yes. Each graph is built from a layout with no crossings, then scrambled.
Do the lines have to stay straight?
Yes. Lines are always straight, so you solve the puzzle only by moving the points.
Is Untangle free to play here?
Yes, with no limit on the number of puzzles. Untangle 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.
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Want a game like this on your own site?
Untangle (planar graph puzzle) (Untangle) 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.