Loop the Loop

Move count:

9999

0

Time:

999999

0

Loop the Loop rules

About the game

Loop the Loop (also known as Slitherlink) is a logic puzzle game played on a grid where some cells are blank, and others contain a number between 0 and 3, called a "clue". The goal is to draw a single continuous loop around the grid by following these rules:

  1. The loop must not cross itself, ensuring only one enclosed region within the loop.
  2. The loop should be closed, with no loose ends.
  3. The number in each cell (the clue) indicates the exact number of sides around that cell that must be part of the loop. For example, a cell with a "0" cannot have any sides connected to the loop, while a blank cell has no constraints on its sides.

Playing the game

  • Choose Your Puzzle: Select a board size and difficulty level. If you're new to this puzzle, start with a smaller board to get familiar with the rules.
  • Marking the Loop: Every puzzle has one unique loop formed by specific edges in the grid. All edges begin as "unmarked", and your task is to identify which edges form the loop, marking these as "active".
  • How to Mark Edges
    • Left-click an edge to cycle through its states: "Unmarked" → "Active" → "Hidden" → "Unmarked".
    • Right-click an edge to cycle in reverse: i.e. "Unmarked" → "Hidden" → "Active" → "Unmarked".

Note: Only the "active" edges matter for the solution. "Hidden" is just a way to keep track of edges you want to exclude.

Here are examples of the three states that the edges can be in:

Unmarked

Active

Hidden

Here are the different clues that a cell can have:

0
1
2
3

In game assistance

  • To help you track connected segments, any segments that are already linked will share the same color, while separate segments will be shown in different colors.
  • Edges that can only take the "hidden" state based on the clues and your current markings will automatically fade (e.g., edges around a cell containing a "0").
    0
  • Any edges marked as "active" that conflict with clues will display as dotted red lines.
    3
  • When the correct number of "active" edges surrounds a clue, that clue will fade to confirm the match.
    2
    2
  • Use the "Undo" and "Redo" buttons to fix mis-clicks / incorrect choices, and the "Reset" button to start fresh if you need to clear all markings.

Tips & Tricks

  1. Try to identify common patterns in the "active" and "hidden" segments, based on the positioning of the clues. For example, see if you can figure out which edges must be "active" when we have diagonally adjacent squares having the "3" clue.

    3
    3
    →
    3
    3
    Click to show

  2. Each puzzle has only one solution. If you find yourself with two equally valid but separate sets of segments, it means an earlier choice was incorrect.

    For example, this situation means that one of previous choices was wrong, as it has two separate possibilities that are both valid.

    2
    ↙↘
    2
    2
  3. Each puzzle is looking for a single continuous loop without loose ends, so each "dot" on the grid must have 0 or 2 "active" segments connected to it.

To learn more

"Loop The Loop" is a popular puzzle first developed by "Nikoli" under the name "Slitherlink". I came across it in a newspaper, alongside other puzzle games such as Sudoku and Kakuro, and had a lot of fun learning and solving it. Wikipedia is an excellent starting point to learn about it and to learn more tips for solving it!