% slitherlink 668 by Otto Janko, http://www.janko.at/Raetsel/Slitherlink/668.a.htm
slitherlink
hard-
24 14
..3...2..2...3..3.3..0..
22..2.32.2230.3.2..1..31
.213.3..22.22...2..3.1..
3....1223..221.21.13.33.
1....22.3.11.2...23.1.21
23.223..123212.3...0..3.
.2........122....3.232..
.2223.33...13....2...3.3
...2...1.12.2020.2..1.12
1..12.2...31.2......3222
23200.23223....2121.....
12.20..2.........32.212.
2.2.222323.13...31..3.22
...3....23.3.1...33.....
