Terence McKenna (1946 - April 3, 2000) was the originator of the timewave zero theory, which claims time to be a fractal wave of increasing novelty, which ends in 2012. (see Eschaton[?]). McKenna's theory is related to the theory of the technological singularity, except that McKenna recommended what he called the Archaic Revival as the antidote to the march of technological progress. This appeared to involve a combination of hallucinogenicdrugs, Gaianism, and shamanism.
... The posterior commicating arteries join the posterior cerebral arteries, completing the circle of Willis.
As the arteries in the circle of Willis form a complete ring, ...