When Cooper returned in 1963, she opened an independent graphic studio in Brookline, Massachusetts. The MIT Press was among Cooper's various clients, leading to her design of its iconic trademark colophon or logo, an abstracted set of seven vertical bars (a visual play on the vertical strokes of the initial letters "mitp", as well as the spines of a stack of books). The logo has been called a high-water mark in twentieth-century graphic design. The commission to design the logo had first been offered to Cooper's old mentor Paul Rand, who demurred and recommended her for the job.