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 entry for December 28, 1962, Indiana records a lunchtime visit by artist Lenore Tawney, after which he repainted the black ground of The Eateria, "completing my chores for [the] gallery [Stable]." He then writes that he prepared dinner for J. (his partner, fashion designer John Kloss), who had been out shopping and delivering an outfit to artist Jane Wilson.

The entry includes a sketch of two diamond shaped canvases, one with the number eight and the other with the number seven, with the note "small paintings started [this] evening." Over the next few days Indiana would work on more diamond number canvases, incorporating them into two four-panel paintings: Small Black Diamond Polychrome Numeral Quartet Summing Thirty and Four Numbers Summing 30.