Normal sudoku rules apply. A) Neighbouring digits on a green German Whisper (GW) line must have a difference of at least 5. B) Neighbouring digits on an orange Dutch Whisper (DW) line must have a difference of at least 4. C) Digits on an arrow sum to the digit in that arrow’s circle. D) Along purple zipper (Z) lines, pairs of digits equidistant from the centre of the line have the same sum. On odd-length zipper lines, this sum is the value of the digit in the central position. E) Digits in a cage may not repeat and must sum to the clue in the top left of that cage (if given). Each constraint type may contain no repeated digits anywhere in this puzzle. Eg. If 2 appears on a GW line then no other 2 may appear on any GW line in the puzzle. Additionally the grid is partially covered in fog. Placing a correct digit may clear fog somewhere in the grid.