To request a vision, kings, priests, etc would give a blood offering to the vision serpent.
The image of huge square snake jaws around a Maya head looking Forward is a common enough glyph.
What I found astonishing was an artistc representation of Athena and a huge serpent which held an exhauster//passed out Jason (Odyssus?) in its mouth ... I will have to check for the source.
Anasazzi, Dogon, dream time Aussies ... Will read the book, thanks.
Athena, Serpent, Jason
Mind is the rider.