Slitherlink (Cipher) by Matej Uher
(This is a bonus “second” puzzle that is not connected to the usual Monday-Saturday week difficulty.)
or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)
Theme: No Four in a Row
Author/Opus: This is the 2nd puzzle from guest contributor Matej Uher.
Rules: Standard Slitherlink rules. Also, the letters X and O stand for two different digits from 0 – 3.
Difficulty: 3 stars
Time Standards (highlight to view): Grandmaster = 2:45, Master = 4:00, Expert = 8:00
Solution: PDF; a solution video is also available here.
Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.