Normal sudoku rules apply. Clues outside the grid are both Sandwich AND Skyscraper clues. As a sandwich, the clue gives the sum of the digits between 1 and 9 in that row or column. As a skyscraper, the clue represents how many digits would be visible when standing at the clue looking at its row or column, if each digit were a building with the height of its value. A "?" in a clue may represent any integer value. Digits along a thermometer must increase from bulb to tip. Digits on an arrow must sum to the digit in that arrow's circle.