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