Theme: Gas Pipe
Author/Opus: This is the 2nd puzzle from guest contributor Gaurav Kumar Jain.
Rules: Standard Sudoku rules. Additionally, if a grey circle is given between two adjacent cells, then the two numbers in those cells must be consecutive. (Note: not all grey circles are given; adjacent cells without a circle may contain either consecutive numbers or nonconsecutive numbers.)
Difficulty: 3.5 stars
Time Standards (highlight to view): Grandmaster = 3:30, Master = 6:30, Expert = 13:00