That text in particular has some importance to the Aikido side of the table,
Frankly, given that you don't understand what ki and kokyu really are, what good does "that text" do you? As I've pointed out a number of times, it's a common theme among Chinese and Japanese that people who can read the common language do not have the background, knowledge of idiom, knowledge of folklore, etc., to read the old texts in the way they were meant. I also mentioned that it is very common in my contacts in the martial-arts world to see some rather ego-centric people who disregard the comedic value of the above scene and prance right ahead.
Seems the Taiji figure in the second backbow illustration of the dynamic underwent a 180 degree rotation. What would one use to describe that dynamic in terms of the physics --- hmmm? Too bad we don't have a Western name for mass undergoing rotations or cyclic displacements or a tendency to do so... really too bad --- Oh wait, silly me, we do -- angular momentum and moments ...
And of course when I do a Taiji form I sometimes bend my knee. What you would see is your own "Aha, angular momentum!" frippery and miss, once again for the thousandth time, the jin/kokyu force resultant that is the important point. But frankly I'm tired of covering the same old ground. Your point seems to be an endless "I can't be wrong! I'm a lawyer! I'm a pilot! I'm a teacher! So let's argue until I'm proved right!". Not me.