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    Re: Medieval Navigation Problem
    From: Frank Reed
    Date: 2019 Nov 26, 12:27 -0800

    Dave, you wrote:
    "I was sure there must be a neater answer, so I rang the author up.  As soon as he said, “imagine the barn on the opposite side of the river”, it all became clear, as did the 3,4,5 triangle for distance."

    Call him up again, and ask if my speculation was right that this puzzle was inspired by the optical analogy and Fermat's Principle of Least Time. :) As I say, I have never seen this puzzle before or anything similar but it jumped right out at me that it was similar to an optics problem.

    Frank Reed

       
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