Richard K. Guy

Richard Kenneth Guy was a British mathematician. He was a professor in the Department of Mathematics at the University of Calgary. He is known for his work in number theory, geometry, recreational mathematics, combinatorics, and graph theory. --Wikipedia

Photo Attribution: Thane Plambeck from Palo Alto, California, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons