% slitherlink 680 by Luke Pebody, http://www.janko.at/Raetsel/Slitherlink/680.a.htm
slitherlink
very hard
19 16
.23.3..3....2...2.3
.22..1.0...3..3122.
.31....2.......2.12
..2.13.2..31.....3.
.3.1...22.....2..22
2.32.2231.1..3....2
..22..2.132..0..2.2
3...2.1.....1..2.30
..21..322....3.3...
.....2..1..........
.....22.23113..2312
2.3.11.....3.3.2...
2.3.3..1.3...1...12
322....3.12..2.2132
...2.112..2220.2222
3.223.2..2..2..3...
