When it hits this glass prism, I know it just looks like a gray triangle to you, but imagine it as a triangular piece of glass, and it's hitting it at an angle.

当它撞击这个玻璃棱镜时，我知道它对你来说看起来就像一个灰色三角形，但想象它是一块三角形的玻璃，并且它以一定角度撞击它。