Find a closed loop that travels horizontally or vertically though each square exactly once so that each number is the sum of the lengths of the two segments that pass through it. Below is an example of a solved puzzle. Each puzzle below has a unique solution.
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |