"It was a sheer stroke of luck on your part, Hawkhurst," he added. 
"Here is a much easier puzzle, because it is capable of more systematic analysis; yet it may just happen that you will not do it in an hour. 
Put Romeo on a white square and make him crawl into every other white square once with the fewest possible turnings. 
This time a white square may be visited twice, but the snail must never pass a second time through the same corner of a square nor ever enter the black squares."

"May he leave the board for refreshments?" asked Grigsby.

"No; he is not allowed out until he has performed his feat."

See answer