Normal sudoku rules apply. Cells separated by a single knight's move (in chess) cannot contain the same digit. Tower Fortress: Cells that are part of the gray tower must be greater than all orthogonally adjacent non-tower cells. Note: any cell that the tower even partially covers is considered a fortress cell. Rapunzel's Sausage: The difference between the sums of two linked sausages on a chain must be exactly equal to the number of sausages in that chain. Rapunzel's Face: The digit on Rapunzel's face shows how many numbers of the opposite odd/even parity to itself appear on the whole sausage chain.