Normal sudoku rules apply. A digit X in a cage points to a second digit Y located X cells away vertically or horizontally. The number in the top left corner of the cage indicates the sum of X+Y. Digits in cages may point to cells inside or outside the grid. Clues outside the grid indicate the digit which has to be placed in the Nth cell in the corresponding direction, where N is the digit placed in the first cell in that direction. Digits along blue lines have the same sum within each region it passes through. The gray area outside the grid is considered one region for purposes of this rule. Different lines may have different sums.