Closed Loop:
In a closed-off region (no path for any lines to escape), there must be an even
number of unconnected segment-ends. Otherwise, it's impossible to successfully establish
a non-self-intersecting loop. Usually, this technique will help you create a line
segment and further solve the puzzle.
We want to determine where the second segment that connects the red dot:
Now we count the number of unconnected segment-ends (numbered in red):
To make the count be an even number, we conclude that the second segment to be going
into the closed-off region:
« Back to Clues/Strategies