Color类、Blue类、Red类和Green类的基础上， 使用运行多态的原理， 为Blue、Red和Green类设计Fill和Draw方法。(Based on the Color class, the Blue class, the Red class, and the Green class, the Fill and Draw methods are designed for Blue, Red, and Green classes using the principle of runni

对象：对象是类的一个实例，有状态和行为。例如，一条狗是一个对象，它的状态有：颜色、名字、品种；行为有：摇尾巴、叫、吃等。(Object: an object is an instance of a class with state and behavior. For example, a dog is an object that has the status of color, name, variety, behavior: wagging its tail, calling, eating