A man running away from the aliens carried with him his pet fox, pet goose, and some corn.
He came to a river which it was necessary to cross. He could, however, take only one across
at a time. If he left the goose and corn while he took the fox over, the goose would eat the
corn. But if he left the fox and goose, the fox would kill the goose. How shall he get them all
safely over?