计算机图形学程序，该程序演示太阳，地球，月亮三者的一个系统，按“y”“m”“d”系统会模拟地球公转/自转/月球绕地球转-Computer graphics program that demonstrates the Sun, Earth, Moon, a system of three, according to " y"　" m"　" d"　the system will simulate the Earth revolution/rotation/moon around the earth, etc.