Slitherlink

Slitherlink also known as  Dotty Dilemma is a logic puzzle published by Nikoli. As of 2005, 17 books consisting entirely of Slitherlink puzzles have been published by Nikoli.

Slitherlink is played on a rectangular lattice of dots. Some of the squares formed by the dots have numbers inside them. The objective is to connect horizontally and vertically adjacent dots so that the lines form a single loop with no loose ends. In addition, the number inside a square represents how many of its four sides are segments in the loop.
Other shapes can be used in lieu of the standard grid, as long as each tile has 4 sides. These include snowflake, penrose, laves and altair. They add complexity by increasing the possible paths from an intersection, but the same rules apply to their solution.

Here is one you can try courtsy of puzzles from the arena.