The Deuces are one of the oldest gangs in Chicago and date back to the White greaser gangs of the 50s. Back then, a gang called the Barons controlled Hamlin Park and a gang called the Blackhawks controlled the nearby projects at Clybourn and Diversey. In the early 60s, the two groups merged and took the name Insane Deuces.
As they explained, Deuce symbolized the two gangs' merger into one. They chose green as their color and adopted symbols like the 2 of spades, dice with two dots and a giant number 2 with a top hat. The Deuces have controlled those two areas ever since.