Normal sudoku rules (mostly) apply: Fill the grid with the digits 1-6 (and 0) so that (almost) no digit repeats in any row, column or box. Each unique digit may appear twice in exactly one row, column OR box. No row, column, or box may contain more than one repeated digit. (eg if a digit repeats in a single box, it must not repeat in any other box, any row or any column). The grid is covered with fog which will lift in a 3x3 area surrounding any correctly entered digit. Numbers outside the grid show the sum of the digits on the indicated diagonal. Digits on a pink line form a non-repeating set of consecutive digits. Digits separated by a black dot are in a 2:1 relationship (i.e. one is double the other). Digits separated by a white dot are consecutive.