An old man gets up every morning, goes out in front of his house and sprinkles a white powder up and down the street. One day, a neighbour who had watched his apparently crazy routine for many years confronts him. "What is this powder you sprinkle on the street every morning?" "It's special elephant powder" the old man said. "It keeps the elephants away". "But..." says the neighbour "Everybody knows that there are no elephants in Nebraska". The old man just nodded "I guess it must be working then!"