% nurikabe 428 by Otto Janko, http://www.janko.at/Raetsel/Nurikabe/428.a.htm
nurikabe
medium-
13 13
...5..3......
..........1..
.3..2..4.....
3...........4
.......2.2...
..4.3.......2
.............
...1..2.....2
.........3...
2...2.2.2..1.
..........1.3
2............
...4.2...4...
