McRae, who were familiar with conformal mappings, was reworked into the final form in early 1937, which was eventually published in January 1939. Starting with a rectangular diagram, Smith had developed a special polar coordinate chart by 1936, which, with the input of his colleagues Enoch B. It was independently proposed by Tōsaku Mizuhashi ( 水橋東作) in 1937, and by Amiel R. Electrical engineers graphical calculator