Tav - Mark, Signature 406
Tav - Mark, signature, lead, Saturn, Cosmic consciousness, administrative intelligence, dominion and slavery
Vav - Nail, tent peg, hook, earthy, Taurus, intuition, triumphant and eternal intelligence, hearing

Tav means "Mark, sign, cross." An X or cross was the ancient Phoenician form of the letter Tav. Ancient Rabbis called Tav "the seal of truth, god, creation". A signature is the mark one makes that states law or truth. We sign a document with our name to indicate that it is true and binding.

"The truth connects."
"Draw into the center and hear the voice of intuition."

Signature of Mark Twain
Signing a document
Even today, someone who can't write signs his name with an "X" or cross.
The original Phoenician form of Tav