Slitherlink
Slitherlink (also known as Fences, Loop the Loop, Ouroboros and Dotty Dilemma) is a logic puzzle. Slitherlink is an original puzzle of Nikoli; it first appeared in Puzzle Communication Nikoli #26 (June 1989).
A Nintendo DS version of Slitherlink, utilising the touch screen interface, was released in Japan by Hudson, titled Puzzle Series Vol. 5: Slitherlink. The eurogamer review rates the game 10 out of 10. Or see pocketgamer.