>>7625481
Where the form reaches it's peak. It's where the two lines meet.
He talks about it a bit in this article.
https://www.muddycolors.com/2020/08/how-to-achieve-a-stronger-likeness-and-what-to-memorize-for-invention/
But that pic is from this one.
https://www.muddycolors.com/2017/03/a-list-of-tools-to-achieve-a-stronger-likeness/