% slitherlink 180 by Otto Janko, http://www.janko.at/Raetsel/Slitherlink/180.a.htm
slitherlink
hard-
20 15
.23.2..221.3......13
.1.3...2.32..2.3.23.
...31.12.2.2.22.212.
221.2..1.331........
3...31......3.2121.3
..3.12.......1...23.
..2.2..11...2..22..2
11.....31..3....22.3
.21.1.2.22..32.311..
....2222...0....3..3
..1..23..21.3.22.12.
..3.3.323..3..233..3
....2..12211120..3..
22.22.22..3.....2.23
.1......23...23.....
