translation.en: Yeah, it's one of those giant camera lenses that takes a picture of the outside world -- it's sort of a little movie, without any moving parts -- and projects it on a page, and you can see the world outside you as you walk around it.
translation.zh: 就是一个巨大的相机镜头一样的东西 可以照出外面的世界 就像个小电影机一样，只是没有任何移动部件-- 它把图象投在一张纸上，你绕着它走过时就能看到外面的景象