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.

Indiana's journal page for February 2, 1962, includes a sketch of Polygon: Triangle, with the artist commenting that he was dissatisfied with his first triangle painting (Tintinnabulation), so he prepared another, with a larger three.

Indiana notes receiving calls from Stephen Durkee and James Rosenquist, both who were planning on seeing the film The Sin of Jesus. He then records going uptown to run some errands, and to the Museum of Modern Art for tea in the lower cafeteria, commenting that the snow in the garden was particularly lovely. He describes the day as "a 'Frank' day," referring to Robert Frank, the director of the two short films he saw, Pull My Daisy and The Sin of Jesus. 

Indiana records having dinner after the films, and picking up paint and lithography pencils at a nearby art store. He notes that he finished an American Eat drawing early in the a.m. of the next day.