He is known as a preeminent authority on the mathematics of paper folding. Hull’s own research has developed some of the mathematical foundations of origami, and his historical analysis has uncovered previously neglected mathematical origami contributions by other scholars. His passion for teaching often combines origami and mathematics, and he regularly teaches origami math to classes ranging from high school to advanced college seminars. His book, Project Origami, explains how origami can be used to teach math—not just geometry, but also calculus, abstract algebra, topology, and more. His origami works, which are mostly modular forms, display the intersection of mathematics and art.