Knot Untangler
A tangle of points joined by straight lines. Move the points — never the connections — until no line crosses another. Every puzzle here is guaranteed to be solvable.
Move the lettered points until no two lines cross. Every connection stays.
FreeOn this device
Puzzle 1: 6 points, 8 lines (density 67% of the most a flat graph can have), 5 conflicts at the start. Every puzzle has a known untangled layout.
Keys: arrows move the focused point, Shift for fine steps, [ and ] switch points.
Conflicts (5)
- A–E crosses B–C
- A–E crosses C–F
- B–C crosses D–E
- B–C crosses E–F
- C–F crosses D–E
Solved on this device: 0 of 12.
Controls
- Drag a point with a finger or mouse.
- With the keyboard, Tab to a point and use the arrow keys; hold Shift for small steps; [ and ] move between points.
- Undo takes back one move and Reset restores the starting tangle. The panel lists every conflict by letter.
The rules
- Lines are straight and always join the same two points.
- Two lines meeting at a point they share are fine. Any other crossing or touch counts, including lines lying along each other and a point resting on a line it does not belong to.
- Points cannot be placed on top of one another (they keep a small minimum distance apart).
Scoring, saving and limits
The puzzle is solved when there are no conflicts. Your move count is shown; there is no time limit.
Your current layout, moves and which puzzles you have solved are kept on this device only. Download a backup to move them.
Each puzzle comes from a grid of triangles, so a crossing-free layout is known to exist — but your solution can look completely different from it.
Questions
- Is every puzzle really solvable?
- Yes. Each one is built from a flat layout with no crossings and then scrambled, and that layout is checked to have zero conflicts.
- Why does a point touching a line count?
- Because then you cannot tell whether the line passes through that point or connects to it. Moving the point slightly clears it.
- Does resizing the window change my layout?
- No. Positions are stored independently of the screen; resizing only changes how big the picture is drawn.