Slitherlink (Sudoku) by Carl Worth
or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between edgex mode where left click+drag draws lines and right click marks X’s and a number entry mode.)
Theme: Clue Symmetry and Logic (inspired by an earlier contest submission from Scott Handelman)
Author/Opus: This is the 9th puzzle from guest contributor Carl Worth.
Rules: Standard Slitherlink rules. Also, enter a number from 0 to 3 into each gray cell as additional Slitherlink clues. Numbers in the gray cells cannot repeat in any row, column, or 2×2 group of gray cells.
Answer String: Enter the length in cells of each of the internal loop segments following the arrows for the marked rows, starting at the top. Separate each row’s entry with a comma.
Time Standards (highlight to view): Grandmaster = 4:00, Master = 6:30, Expert = 13:00
Solution: PDF
Note: Follow this link for other Slitherlink variations and this link for classic Slitherlink. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on.