George Trevor, longtime New York newspaper writer, invoked quadrilateral in describing Bobby Jones’ 1930 Grand Slam:

“Atlanta’s first citizen, like Napoleon before him, has stormed the supposedly impregnable ‘quadrilateral.’ Bob is the first golfer in all history to win the four major championships—American open, American amateur, British open and finally the British amateur.”

Today the Grand Slam consists of the Masters, PGA Championship, U.S. Open and The Open Championship but remains an impregnable quadrilateral.

The Quadrilateral’s was designed by Tom Naccarato. The look was inspired by vintage publications from the Jones era and meant to signify The Quadrilateral’s reverence for the majors, history and those pre-clickbait days when folks dressed better and some golfers even dared to get mechanical engineering degrees.