xkcd #3125: Snake-in-the-Box Problem
Title text:
Chemistry grad students have been spotted trying to lure campus squirrels into laundry hampers in the hope that it sparks inspiration.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3125/
The difficulty is that the goat is tied to the fence.
It would be a lot easier to put a pole in the center of the circle.
The length of the rope would then be 0.5 x sqr(2) x fence radius.