Once upon a time there was horse. It nibbled the grass, galloped around, and lived in peace. Then a programmer came along, and suddenly the horse had a descendent — Pegasus, a winged horse. This new beast inspired others to take on multiple jobs. It was like a horse: it knew how to nibble grass and gallop. But it also knew how to fly. This is how subclasses appeared in Java. The details are in the lesson.