Square http://en.wikipedia.org/wiki/Sator_Square The  Sator Square  is a  word square  containing a  Latin   palindrome  featuring the words  SATOR AREPO TENET OPERA ROTAS  written in a  square  so that they may be read top-to-bottom, bottom-to-top, left-to-right, and right-to-left. The earliest known appearance of the square was found in the ruins of  Pompeii