Slitherlink, like most logic puzzles of its ilk, is built on a few simple rules, but can be devilishly devious.
- Rule 1: Lines are drawn on the edges of cells. In this version of the puzzle, just click the edge to draw a line. Click again to erase it.
- Rule 2: Numbers inside a cell indicate how many edges (out of four) are drawn in the final solution. If a cell contains no number, you are free to draw as many lines as you need around it (keeping in mind Rule 3), but if a cell has a zero in it, you may not draw any lines. When you have the right number of lines drawn around a certain cell, it will turn bright. Be careful, though, as the cell will turn bright even if the lines you drew were not the correct ones!
- Rule 3: All of the lines must be incorporated into a single non-intersecting loop. That means NO loose ends, NO figure eights, and NO DICE trying to use two or more closed loops to solve the puzzle.
Analysis: Luke has put together a nice flash implementation of Slitherlink, and has provided 75 puzzles for you to solve. He's even grouped the puzzles by difficulty. The interface is straightforward and professional, with lots of pleasant curves instead of harsh boxes. There's no music, but there are some minimal sound effects when you draw or erase a line, and a little melody plays once you solve the puzzle. That's a smart choice by the author—music would only serve to distract the player from the real meat of Slitherlink. The only thing I would add is a way to mark which segments should NOT be drawn. These are just as important to keep track of as what lines you should draw, if not more. Something as simple as a second click that brings up a little "x" would suffice. For now though, you'll just have to rely on your memory. Update: As Anders points out in the comments, you may place crosses to mark segments with the combination [space] + left mouse click. (Thanks, Anders!)
So if you enjoy or have ever enjoyed puzzles like Sudoku, Minesweeper, Nurikabe, Fillomino, or any others like them, give Slitherlink a try. Go on. It won't bite. I promise.