(An entry in The Lives of the Mathematicians)

Norbert Wiener was notoriously absentminded. Once, just after he moved house in Princeton, he returned to the street where his old house was. Unable to find his home, he spotted a little girl playing in the street and asked her: "Little girl, do you know where I live?"

"Yes," she replied. "You live on so-and-so road number such-and-such."

"Thank you. You're a very clever girl," he added; "it's lucky you were here today."

"Yes, I know, father," she said. "Mother said I was to wait for you here."