If we abstract this process, and simplify it as much as possible, then we could start with a single sheet of paper, one surface, and we could make a fold and divide the surface into two surfaces.
如果我们提取这个过程，并将它尽可能地简化 那么我们可以从一张纸开始入手 在一个面上我们对折 使它形成两个面