"Once Indiana had perfected such rich formal complexities that integrated design, color, and lettering, he was able to address a category of subjects with special personal and artistic appeal, homages to other American painters with whom he felt an emotional and stylistic affinity. Three in particular belonged to the first American avant-garde of the early twentieth century-Joseph Stella, Charles Demuth, and Marsden Hartley. In their work he found compositions with flat opaque panels of color, letters and signage, and abstracted symbolic portraits. Indiana's references to these American predecessors maintained his mechanical hard-edged style, bold color designs, and string graphic sensibility, but were different in their derivation from previous works of art, reinterpreted in a contemporary Pop idiom and tied into Indiana's own biography."
(J. Pissarro, "Signs into Art," Robert Indiana, New York, 2006, p. 154)