'pythagorean precision / pythagorean accuracy'

What does ‘pythagorean precision / pythagorean accuracy’ mean? If the object was handcrafted with ‘pythagorean precision’, what does it mean? The barber trimmed the hair on the back of his neck with ‘pythagorean precision’. What does that mean as well?

Thanks.

Something is exact and has been completed very meticulously and carefully.

Pythagoras, the Greek philosopher and mathematician (though actually more a mystic) supposedly believed that mathematics and numbers, were the ultimate reality, and he founded what amounted to a religion around them. Since he was calculating everything-- the stars, the planets, music-- he could be considered quite ‘precise’.