Cave by William Hu
or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)
Theme: Surrounded by 258
Author/Opus: This is the 9th puzzle from guest contributor William Hu.
Rules: Standard Cave rules.
Difficulty: 2.5 stars
Time Standards (highlight to view): Grandmaster = 3:45, Master = 4:45, Expert = 9:30
Solution: PDF and solving video.
Note: Follow this link for classic Caves and this link for Cave variations. If you are new to this puzzle type, here are our easiest Cave Puzzles to get started on. More Cave puzzles can be found in Roger Barkan’s Colossal Cave Collection, in The Art of Puzzles, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.
11:04 with trials and errors method. I wonder what I missed
8:30 Took me a while to suss out the logic.
10:22.Hard puzzle. Looking forward to solution video !