Once upon a time, there was a wise man who told the people of the Earth that the Heaven was round and the Earth was square. Since he was a wise man who had taught them much of what they knew, the people accepted this as truth, and this truth reverberated throughout all the lands.
They wrote it into their scriptures (Ezekiel 7:2 , Isaiah 11:12 ) and stamped it on their coins. They enshrined it into their architecture and temples. They even wove it into the fabric of their myths, legends, and history. I detailed one of the legends in my posts,( I Ching, Made in Vietnam, Part 4 ) regarding one of our famous kings, Lang Liêu. It became part of our axiom of truths.
Fast forward thousands of years later and the modern civilized humans could see from their scientific observation that the Earth was, in fact, round, and Heaven, as far as the senses and instruments could tell, was boundless. Sheepishly, the people laughed at their ancestors’ apparent gullibility, some even felt a bit of sympathy for the way that their ancestors, common and coarse as they were, had been hoodwinked by this old wise man all these thousands of years.
Then they went about changing all their scientific data, even managed to rewrite certain sections of their scriptures, citing a poor translation effort as the excuse of how the passages reading ‘square corners of the Earth’ ever got there in the first place. However, some still clung onto the ancient notion of a square Earth, even to this day.
We call these die-hard people, Flat Earthers.
Still, the vast majority of the people on the planet now know the unambiguous truth, namely that the Earth is round and the heaven is boundless.
But I’m a Taoist, you see, and we Taoists need to go deeper into our thought processes and look at what was presented. After all, nothing is ever as it seems, and if I have learned anything about Taoism by now, I know better than to just simply take things at face value. I have found that there are always layers of meanings embedded within even the most basic of axioms, which meant that there had to be another reason why our ancient ancestors told us that the Earth is square and the Heaven is round.
I decided to take a closer look at this phenomenon. First I simplified it down to a line drawing of a circle and a square.
Then I compared it to what the I Ching also said in regards to this axiom.
My ancestors had told me that Heaven is a circle. The I Ching denotes Heaven as Càn (Ch’ien /天).
They also told me that the Earth is a square. In the I Ching, the Earth is Khôn (K’un /地).
The merging of these two hexagrams give us this:
Yes, yes. I know I’ve put too much information into this bagua (thunder and wind and such), but for now, just ignore the other parts and simply focus on Heaven and Earth.
Now, Taoists know that heaven and earth are not static things. They are forces that constantly move and change, going from one polar to the other in rapid succession, and it is this movement that allows for the chi to be expressed.
Since the yin yang symbol is a sphere with Heaven and Earth circling through it, the movement within the circle will obey certain mathematical rules, namely spin.
To show this mathematically, it would look like this:
This is the formula for angular momentum. I also found a good definition for it.
The angular momentum of a rigid object is defined as the product of the moment of inertia and the angular velocity. It is analogous to linear momentum and is subject to the fundamental constraints of the conservation of angular momentum principle if there is no external torque on the object. 
Can you imagine trying to explain angular momentum to people who barely understood that if you wash your hands you won’t get sick as often, or that it really isn’t a good idea to stare at the sun because you could hurt your eyes really badly?
Well, there is an easier way to teach people basic concepts–or at the very least, show them how to preserve the knowledge in easy to transfer pieces of information and hope that in the far far future, their children would be able to look at the pieces and put them all together.
Let’s put them all together.
Everything starts off with Heaven.
(continue to Round Heaven, Square Earth: Part 2)
 Angular Momentum