Normal sudoku rules apply. The grid is partially covered in fog. Placing correct digits will clear the fog from surrounding cells. One cell in each row, column and box is lighter than normal. Lighter cells have a value equal to half of their digit. Each digit from 1 to 9 appears once in the set of lighter cells. One cell in each row, column and box is heavier than normal. Heavier cells have a value equal to one and a half times their digit. Each digit from 1 to 9 appears once in the set of heavier cells. No cell is both lighter and heavier. Box borders divide a line into segments whose values sum to the same number. Lines do not branch, cross or share cells.