"Do the best you can until you know better. Then, when you know better, do better." Normal sudoku rules apply. Echo Lines: Indigo lines are filled with a repeating sequence of one or more different digits. The full sequence must appear at least twice along the line and must always repeat in its entirety. Different lines may contain different sequences. Nabner lines: No two digits on a yellow line may be the same or consecutive. Killer Cages: Digits in a cage may not repeat and must sum to the given total.