Responding to 9/11, Indiana concentrated on a separate series of canvases, also based on a theme from the sixties, the Yield Brother theme, centered around the Peace symbol. Again he introduced and combined colors not regularly used before, often juxtapositions so intense that some outlines optically seemed to vibrate as white lines. Lamenting the unresolved conflicts in Afghanistan and Iraq, short phrases about the loss of peace filled the central circles of these compositions. As he has done from the beginning of his career, Indiana continues to project himself into his art and forcefully engage the history and culture of his country.
— John Wilmerding
John Wilmerding, Joachim Pissarro, and Robert Pincus-Witten, Robert Indiana (New York: Rizzoli, 2006), p. 167.