About:

The Sator Square is a word square consisting of a five-word palindrome:

S A T O R
A R E P O
T E N E T
O P E R A
R O T A S

If read top to bottom, left to right it creates a palindrome: "sator arepo tenet opera rotas". The exact translation is unknown and speculated, but a common interpretation is "the farmer Arepo works a plough".
It is unknown what exactly the purpose of the Sator Square was, it spread like a meme within ancient times, and is possibly the oldest meme in human history. But of course "The year is invalid" so I have to spread LIES AND SLANDER so I can make this article exist.

Origin:

The Sator Square's true origin is unknown, but the oldest one discovered was found in Pompeii.

Spread:

Do I look like a time traveler?

Various Examples:

Search Interest:

External References:

https://en.wikipedia.org/wiki/Sator_Square
http://mysteriouswritings.com/the-sator-square/
http://www.taliscope.com/Sator_en.html