HeTu

Before we contemplate about Zhong Tian, consider these: -

The early Chinese (the time of the 4 sage emperors) does not concern so much as to the sitting and facing of their homes. Their main concerns are the community. So, the EH is used to assist them in locating prosperous spots. It is all location, location and location.

EH BaGua is imagery, Xiang of the cosmos. To understand its attributes, EH Numerology is invented. This is another component called Shu. So HeTu is derived to interpret the EH BaGua. HeTu is derived from the understanding of Qi, the 5 elements. As the saying goes, Heaven bestow, Earth receives, Qi originates from Heaven and settle underground as in the forms of mountain (Gen) and rivers (Dui). Such manifestation is called as above, so below. As above there are asterisms. As below there are mountains and rivers which we called Dragons. So, it is believed that the working mechanism of Qi must follow an order. This order is HeTu. So, Shu, Qi and Xiang are complete.

However, have we ever thought that HeTu is also in 3D?