For each of the four marked 9x9 grids, normal sudoku rules apply. A gray line is a palindrome, reading the same backwards and forwards. Box borders divide a blue region sum line into segments with the same total. Different lines may have different values. Digits in a cage can repeat in different sudoku grids, but cannot repeat within a single sudoku – they sum to the total given. Digits separated by a black dot have a 1-X ratio where X is the number on the dot.