In a Slitherlink puzzle, you need to construct a single closed loop connecting points of a grid such that each number clue counts the number of adjacent loop segments. Normally, a Slitherlink puzzle does not permit "crossings", but I am going to relax that rule today. Whenever such a crossing occurs, interpret it so that the vertical line is going over the horizontal line. Specifically, consider the following examples.
The first is not allowed because it won't form a closed loop. The second is a false interpretation of a 4-way crossing. The third is the valid interpretation. Remember: the interpretation of crossings is important because there can only be one loop. Different interpretations of these crossings may disagree about the number of loops.
You may assume the solution is unique. Here is the puzzle:
..21....1 33.1.1133 .13..3... 3..2131.2 12.1.2..3 .3.2312.. ..22.2.2. 12.1.3232 .31.2112.
And a bonus: Is the loop a knot?