Normal sudoku rules apply in the 9x9 central grid. Numbered Rooms: All outside cells on the thermo must contain a digit. That digit must also appear in the Nth position looking into the grid in the row/column, where N is the digit in the first position. Slow Thermometer: Digits on the slow thermometer must not decrease, starting from the bulb end (the circle). The white dot separates consecutive digits. The black dot separates digits where one is double the other. The X separates digits that sum to 10.