最近实现的 canvas 动画小 demo，拖拽小球，自由落体，碰撞反弹，没有任何插件引入。
A recently implemented canvas animation demo featuring a draggable ball, free-fall motion, collision rebound, all achieved without any external plugins.
鼠标拖动黑色小球，鼠标松开后小球自由落体并弹跳。
Drag the black ball with the mouse, and upon releasing the mouse button, the ball undergoes free fall and bounces back.
demo 地址：https://xiaowuqiqi.github.io/canvas-pellet-collision
