The shape of the piano is large at one end, the strings are drawn from the thin end, and the process diverges to the other end. As stated in ancient books, the curved piano surface symbolizes the sky, and the flat piano bottom symbolizes the earth. The so-called "the sky is round". Harp is a standard rectangle with parallel strings.
The number of strings of the harp is different from that of the harp, which is usually 7 strings. However, there are generally many strings in the far north, from 50 strings in ancient times to 25 strings now.