No text, but a visual code

[ololololo]

To say that the water of Quire 13 is green because it was copied from De Balneis Puteolanis strikes me as mere conjecture, entirely without foundation.

Why?
Naked women bathing and the green color of the water. This is quite a significant similarity.

I recently cited the 2011 article by the american scientist couple Lincoln Taiz and Sandra Lee who hypothesized that Quire 13 deals with plant physiology, with the female figures representing the souls of the plants. It was the first time an alternative vision was proposed—a hypothesis that also had the merit of linking all, or nearly all, parts of the Voynich and giving them a unified meaning.

It's also a bias to expect that all topics are somehow interconnected. They don't necessarily have to talk about the same thing. It is quite normal for an herbalist to have a section with astronomy, where the months of planting, treatment, etc. will be indicated; to have a section with anatomy in order to gain better medical knowledge; to have a section with recipes and spells that were an integral part of medieval medicine.
Of course, they may be right, I'm not arguing.