Slitherlink Rules

Slitherlink is probably one of the first Nikoli puzzles I discovered that did not originate in America.  Kakuro and Sudoku both originated with Dell Pencil Puzzles as Cross Sums and Number Place before they traveled to Japan and back again with the Japanese names.  But, this is about Slitherlink, not those. The rules are summarized below.

1. Draw a single connected loop between the dots that does not touch or cross anywhere in the grid.
2. Lines may only be horizontal or vertical.
3. Numbers indicate how many sides in the imaginary square surrounding that number that the loop passes through.
4. Unnumbered squares may contain any number of lines surrounding the square.

An example with its solution is shown below.

There are many strategies and patterns that can be used in solving Slitherlinks.  Perhaps the most well known are the side-by-side 3's, and the corner 3's as well as what I call 'cascading 2's', which is what happens when there is a series of 2's in a diagonal.  Really clever puzzle designers can also force the loop to take a path where there are no numbered clues, but bounce around from dot to dot simply because there is no other path to take.  The possibilities are endless, and even after many years of solving, I'm still learning new strategies.