Voynich's anatomy

[Jorge_Stolfi]

I think it's very strange to consider artists to be so stupid and "free."

The people who drew the illustrations on luxury manuscripts were presumably chosen for their skill at producing nice-looking images.  For "technical" or "working" copies of manuscripts, the customers would not be picky on that point.  They would usually be able to gloss over artist mistakes, and figure out the original intent.  

According to Wikipedia, the Screw of Archimedes was a popular device in in the Roman era, but fell out of use by the 3rd century.  Presumably it was displaced by the You are not allowed to view links. Register or Login to view. or other devices.  So it is very likely that the artists who copied that "notebook" never saw one and ha d no idea of what it was.

All the best, --stolfi