Paper-cutting can not only be a pattern pasted on windows, walls and stakes, but also a kite flying in the sky; paper-cutting is not only flat, but also three-dimensional; paper-cutting can not only cut out a simple and smooth shape, but also a complicated "Qingming Shanghetu". Do you know all these unique features of paper-cutting? Let's fly through the clouds and see the exquisite paper cuttings up close.