Six laws or eight laws. Who proposed it?

Reading Lin Yutang's China Calligraphy, I mentioned Zhao Mengfu's view on the homology of calligraphy and painting, and quoted a poem by Zhao:

Stone is like flying white wood, like printing, and the six methods are connected with the eight methods.

If anyone can learn this, you should know that painting and calligraphy are the same.

I looked it up on the Internet. This is Zhao Mengfu's poem with the title after the volume of "Figure of Qi Lin in Shi Xiu". The original poem is:

Stone flies like white wood, and it takes eight methods to write bamboo;

If anyone can learn this, you should know that painting and calligraphy are the same.