Normal sudoku rules apply. The grid is covered in fog. Placing correct digits reveals clues in the surrounding area. If the grid is rotated 180 degrees, the matching cells add up to 10 e.g. R3C2+R7C8=10. For this purpose, the puzzle's central digit adds to itself. Digits an equal distance from the center of a lavender 'Zipper Line' sum to the digit in the middle of that line. Adjacent digits on a green line differ by 5 or more. All lines are exactly 5 cells long, only move orthogonally and don't share cells with other lines.