Two faces?

[heylise]

Chris, somehow I overlooked your link. Found it now... This is absolutely wonderful!
I am playing around in it now and having a great time!!

Extremely interesting to compare the color schemes.

 

[heylise]

... My own theory is that they coevolved, simultaneously. But the trigram associations did not emerge fully formed. They grew over many centuries and didn't stop growing when the Shuo Gua came out. I believe the first mention of them in literature is in the Zuozhuan, but my book outlines a number of reasons why I think they were part of the original thinking.

I completely agree with all of this. Especially with the trigrams being part of the original thinking.