Normal sudoku rules apply. The value of digits within a cage must sum to the small clue in the top-left corner of the cage. Digits must not repeat within a cage (but values may repeat). The value of digits along a thermometer must increase from the bulb to the tip. There are 9 Hot cells contained within the grid comprised of a set of the digits 1-to-9. Each row, column and box contains exactly one Hot cell. There are nine 9 Cold cells contained within the grid following the same rules as the Hot cells. A cell may have only one of these roles. For cages and thermometer values, Hot cells increase the value of the contained digit by 1; and Cold cells decrease the value of the contained digit by 1.