Y heads. Is this why they get the black eye when they have a partial callistomy ti remove their empathy and are ‘split brains’

Upsilon is known as Pythagoras' letter, or the Samian letter, because Pythagoras used it as an emblem of the path of virtue or vice.[13] As the Roman writer Persius wrote in Satire III:

and the letter which spreads out into Pythagorean branches has pointed out to you the steep path which rises on the right.[14]

Lactantius, an early Christian author (ca. 240 – ca. 320), refers to this:

For they say that the course of human life resembles the letter Y, because every one of men, when he has reached the threshold of early youth, and has arrived at the place "where the way divides itself into two parts," is in doubt, and hesitates, and does not know to which side he should rather turn himself.