说明：  运行程序，屏幕上显示出蓝色背景，当不断重复单击动画工具按钮时，彩色小球发生如下变化：一个小球下落、定格，增加一个小球下落、再定格
(Run the program, the screen shows a blue background, animation tool, repeated endlessly, click button, the color changes of the ball took place as follows: the fate of a small ball, fixed to increase the whereabouts of a small ball, and then fixed)