圆桶中间的的三棱镜，我是用铝箔纸做的，过段时间我会上传制作过程，如果你有镜子的话可以换成镜子，那样会跟会更加清晰，另外还需要两片透明的塑料片

The triangular prism in the middle of the barrel was made of aluminum foil. I will upload the production process in a while. If you have a mirror, you can replace it with a mirror, which will make it clearer. In addition, two transparent plastic sheets are needed