To play, click on the line between vertices to toggle between on and off. The lines must be connected together into one loop as per the rules explained on the Rules tab. A second click can mark a line as "disabled". You can also click on the tile space and then hit the spacebar to toggle between white and gray. This has no influence on the solving of the puzzle, but can help visualize the land in between the lines of the full loop.

Enter puzzle code (1-0) or descriptor (see "Puzzles" tab):

The full set of rules for Slitherlink can be found online. The simple description includes two basic rules. 1) You must connect adjacent dots with horizontal and vertical lines to make a complete loop that never crosses or touches itself. 2) A numbered cell indicates how many lines surround it; empty cells may be surrounded by any number of lines. Numbers that have been violated with too many lines will be rendered in red. The whole puzzle's border will turn green upon successful completion. Intersections with more than two lines will turn red indicating illegal connections.

This playground was written using javascript and is available open source. More later.

Puzzles can be invoked by either a numerical entry from 1-0, or through a character description of the puzzle itself. The numbered puzzles are hand-crafted of varying difficulty, roughly easy to hard. To describe a puzzle, the character string must be of the form: "WxH:<descriptor>", where W is a number indicating the width of the grid, and H the height. The descriptor is a definition of the grid contents from left to right, then top to bottom. A dash '-' can indicate an empty cell. For easier description of sparse puzzles, letter values from 'a' to 'z' can indicate 1 to 26 empty cells, respectively. A dot '.' can be used as a separator, for example between rows. An example descriptor is as follows: "7x7:1b2a13.0a2d.b3a30a.3b2b1.a31a2b.d2a3.02a3b3".