What does it mean to meet Yin and Yang in Feng Shui?

1 intersection of mountains and rivers (Qingnangjing: Yang turns left and Yin turns right to meet. ) 2 acupoints. The nest is full of yin milk ... (Jingjing Wing: Baiyuyuan. Yin turns to Yang. Whoever knows the meaning of circle is a fairy on earth. There is another cloud: Yin comes to Yang, Yang comes to Yin, and Yin comes to Yang.