《易传·说卦传·第五章》
后天八卦是用，代表了八个方位的空间，八个卦的空间排列规律，是横向的，代表了空间。
离也者，明也，万物皆相见，南方之卦也，圣人南面而听天下，向明而治，盖取诸此也。
Acquired Bagua is used to represent the space of the eight directions, and the spatial arrangement of the eight trigrams is horizontal, representing space.