What does the double needle of Feng Shui compass mean?

What does the double needle of Feng Shui compass mean? -the "harmony" of the compass means "depend, depend on that side". If you sit on Zishan, Zishan Bingzi's bonus is to sit on the mountain at noon, and Zishan Gengzi's bonus is to sit on the mountain at noon. With the center of Zishan Mountain as the boundary, 7.5 degrees on Renshan side is Ren Jianshan, and 7.5 degrees on Guishan side is Jian Guishan. Why do you say "concurrently"? The reason is that the "layout" of each mountain is not necessarily so absolutely accurate, but it is definitely different. Another meaning of the master's teaching his disciples is: you should leave room, the compass is not absolutely correct, and it is true to avoid forced use.