Escher's art, Smith chart, and hyperbolic geometry

The purpose of this article is to point out a conceptual link between an artistic creation by the well-known Dutch artist M.C. Escher (1898-1972), called Circle Limit IV (woodcut, 1960), and the most commonly used graphical aid in microwave engineering work, called the Smith chart (1939-1944), created by the U.S. engineer P.H. Smith (1905-1987)