Can the loop touch itself?
It can touch at corners but cannot share edges or cross.
What does a 2 mean?
Exactly two of the four edges around that cell are part of the loop.
Is guessing ever needed?
Well-designed Slitherlink puzzles are fully logical.
How do I mark an excluded edge?
Most interfaces use a second click or a cross mark.
What size grids are common?
Beginners often start with 5x5; advanced puzzles can be 20x20 or larger.
