一个小游戏，俄罗斯方块，基于例程代码改写，加入了背景音乐，启动动画，背景图片，时间显示，日期显示，难度设置等等功能-A little game, Tetris, based on the example code rewrite, adding background music, start the animation, background images, time display, date display, difficulty settings, and more functional