Normal sudoku rules apply. Digits may not repeat in cages. If a cage contains a clue in the top left corner, that cage must be comprised of 1-, 2-, 3-, and/or 4-digit numbers that sum to that value. Numbers are made from either horizontally adjacent digits read left-to-right; or vertically adjacent digits read top-to-bottom (ie numbers cannot bend!). Every digit within a cage must be part of exactly one number, and numbers may not cross cage borders.