Three wise men
bin Hassad, an ancient Arabic mathematician, travelled far and wide. Once he was told a story about an incident in the history of one Arabian village
The village elder put it this way: "O bin Hassad, famed wise man! Holder of the Logical Eye! We once had three wise men. Not as wise as you, of course, Wisest of the wise. One day they were sitting under that tree over there. They were talking and talking as they always did, and when the afternoon drew on, they all took a nap - a custom to refresh their considerable minds. But when they were all asleep, a naughty young child from our village, painted their heads. When they woke up they all started laughing at what they saw. But suddenly, one of them stopped laughing. Why?"
"Well", said bin Hassad, "because..."
What did bin Hassad say?