用类层次关系，模拟动物的飞行。动物有雄鹰、燕子、蜂鸟，企鹅，鸭子；还有松树、蝙蝠；昆虫有蝴蝶、蜻蜓、蚂蚁等。-Relationship with the class hierarchy to simulate the flight animals. Animals eagles, swallows, hummingbirds, penguins, ducks　there are pines, and bats　insects are butterflies, dragonflies, ants and so on.