Douglas Hofstadter is College of Arts and Sciences Distinguished Professor at Indiana University, Bloomington. His books include the Pulitzer Prize–winning Gödel, Escher, Bach; Fluid Concepts and Creative Analogies; Le Ton beau de Marot; I Am a Strange Loop; and Surfaces and Essences. Aside from being a cognitive scientist focused on analogy-making, he is engaged in art, music, and translation. Scott Kim (scottkim.com) is a puzzle creator and graphic designer who has been making ambigrams since the 1970s. His 1981 book Inversions: A Catalog of Calligraphic Cartwheels was the first book of ambigrams ever published.