The gray cells on the playing field are not very attractive, but you can color them in Fill. But this must be done according to special rules. All cells must be filled, while painting must be done in one line, without interruption and without entering the field twice. The line may be curvy, but must not cross anywhere. The game has four levels, but once you click on any of them, a set of sublevels will appear. There are twenty of them on each, which means a total of eighty. You cannot start from the end or from the middle, the levels must be completed in order in the Fill.
