[dwringer]

If it's the second frame of the three-panel strip, then, as another commenter hints, the trick is not to double back. You must complete a circuit around the map. I got frustrated and quit long before trying this until reading that comment, but it (arguably) pays off.

[vinc]

It's the first frame, I read the comments and still I don't understand. The game is too stressful for me, I give up haha