4.25 x 3.75 inches, sight. A note on the back reads: "sketch made by Naum Gabo, when I interviewd in in the summer of 1966 (?) for article in Harvard Connection Magazine, matking point about the function of his sculpture for the De Bijenkorf dept. store in Rotterdam (each new building, he said, was supposed to have a "bump" to avoid monotonous long stretches)