# Slitherlink

## Background

Slitherlink was invented by Nikoli and first appeared in 1989.

## Puzzle and Goal

A standard unsolved puzzle consists of a rectangular grid containing some numbers ranging from 0 to 3.

The goal is to draw a loop along the edges of the grid.

## Rules

The solved grid must satisfy the following conditions:

Each number clue indicates the number of sides of the containing cell that contain a segment.

There is no restriction on the number of sides for cells that do not contain clues.

The resulting loop is a Jordan curve (that is, it is a single non-intersecting closed loop).

## Variants

Slitherlink grids can also have other geometric patterns, in which case the maximum number is one less than the number of sides of the largest polygon in the grid.

## Other Names

Dotty Dilemma; Fences; Gartenzaun; Great Wall of China; Heiliger Pfad; Loop the Loop; Loopy; Number Line; Ouroboros; Rundweg; Schlangenlinie; Sli-Lin; Suriza; Surizaarinku; Takegaki

## Playable Online