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."