Robert Indiana kept a series of illustrated journals during the late 1950s and 1960s, in which he discusses the development of his work as well as his daily life on Coenties Slip.

In his journal page for January 16, 1962, Indiana discusses working on a diamond canvas, the "2nd EAT, [this] one green on red." The entry includes a sketch of the panel, titled Green Diamond Red Eat, and measuring 60 x 60 inches (square), 85 x 85 inches (diamond). Below the sketch, Indiana explains that he painted the letter "A" in the early hours of the morning, and finished the others that afternoon. The artist often added comments to his journal entries at a later date, here "Walker Art Center" refers to the institution that acquired the completed work, The Green Diamond Eat/The Red Diamond Die, in 1963.

Indiana also documents going out for lunch, running errands, and being followed by a patrol car on his way home. He then details an afternoon visit by the art critic Gene Swenson, who saw Indiana's London and early New York works.