% nurikabe 437 by Otto Janko, http://www.janko.at/Raetsel/Nurikabe/437.a.htm
nurikabe
medium-
13 13
2..3..2...4..
............1
....4..1...4.
3....1.......
....3..4.....
...........1.
..2...1..2...
............4
..3.......3..
4......3.....
.............
4............
...3.3.2.3.2.
