中文说明：本程序是描述双摆在重力影响在，任给定初始位置双摆运动的运动仿真。个人觉得非常实用，且来源网站还有许多经典程序和教程。强烈推荐，这是国外上课的教材，大家可以一起了解下国外的课程。
English Description：
This program is to describe the motion simulation of double pendulum at any given initial position under the influence of gravity. I think it is very practical, and the source website has many classic programs and tutorials. It is highly recommended that this is a textbook for foreign classes. You can learn about foreign courses together.