% slitherlink 660 by Otto Janko, http://www.janko.at/Raetsel/Slitherlink/660.a.htm
slitherlink
very hard
36 20
.2.3..3.....2...20..3..3213....1..3.
3121212.22....22.22.1......2....3.13
...2..2.3.3223.....2.3..2.23.3.....2
.2...13....2.2.2.3.3.3..2.....3....2
..2.21.1.31.2..3......12.2..2122.3..
3..2.......2..2212..2.3..02.2...132.
...01...3..3...3.1.....1.3.2123.22.3
3032.23.....2.2.2230.3........1.....
......212212..123...1.....2..1..12..
3..3.2....2...2213.3......2.2.2..3.2
3..0222..........2..232..3.32..30222
.2..3.1...22.3...2.3...1...2..1..2..
222.1.12213.....31..1.2..1213.1..11.
..3.3.32.2..3.22...223...3.1.322.3..
3...1.112...02.2..23....2....1.2.2.3
.11.3..3.22.2....3..12..2.23.3.11.2.
.2....1.....0.221.222.23.20..2...32.
..21.2....22.3....22232.2....2.2.223
.3.32.2..12.2...223222222..2.21.3..2
..12..1.23.1......2.23.3.3.32...2...
