Enigma 154: The more fool you
16 December 2013
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From New Scientist #1299, 1st April 1982 [link]
In the heart of Moreland live many tribes of whom half are sworn to tell the truth and half always to lie. Always, that is, except on April Fool’s day (now an integral part of their culture after introduction by the white man). On this day, liars may “April Fool” if they have heard a truth tribesman fool (i.e. tell a lie when expected to tell the truth). All “truth men” are able in the same way to April Fool if they have heard a liar do an April Fool (i.e. tell the truth)!
I happened to be on safari in the region one 1 April, and I reached a crossroads just as three tribesmen came from the other directions. I asked the first: “Which way to the Umbulu River?” He told me that if he was April fooling, he would say turn right. (Dashed unhelpful these natives!)
The next said: “I assure you it’s left, and also that the third man is from my tribe.” To which the third said that one person was April fooling me, and that I should go straight ahead. After some thought, I took the correct road to the river…
Who was April fooling whom, and which way did I go?