Normal sudoku rules apply. No domino in the grid can contain digits summing to 10. There is some fog in the grid; placing a correct digit might remove it. No guessing is required. Digits in a grey box cannot repeat. There are lines in the grid that connect boxes; the digits in a box are summed to arrive at a value. That value applies to the following rules: 1) Zipper: when box values equidistant from the centre box on a pink line are summed together, they are equal to the centre box's value on that line. The centre box is notated by a pink circle; 2) Modular: every run of three boxes on a teal line must have a different remainder when divided by 3 (ie one value from each of 0 mod(3), 1 mod(3), and 2 mod(3)); 3) Box values on a purple line make up at a set of consecutive, non-repeating values; 4) The box values connected by a blue line must be the same; 5) Box values joined by a white dot have a difference of 1.