WIM no. 17 Spring 2020

מכון ויצמן למדע The artistry of math Folding together creativity and calculation, the flexigon is a new hit M ost discoveries are driven by a search for answers to specific questions, but in some cases exploration simply starts with a playful use of material. The story of the flexagon—a flat paper model that has been inspiring and challenging mathematicians and physicists for years—began with an extra piece of paper. When the British mathematician Arthur Stone, who in 1939 was a student at Princeton University, found that he could not fit American paper into his English binder, he decided to cut them to size. While sitting in class, he started folding these excess strips of paper into different shapes—and one of them caught his eye. Stone showed this shape, which later got the name “trihexaflexagon,” to the theoretical physicist Richard Feynman, as well as two mathematicians, Bryant Tuckerman and John Tukey. Together, they formed the Princeton Flexagon Committee and dove into the world of flexagons, making calculations and developing models. The Feynman diagram, which has become a fundamental tool in particle physics, was one of them. Hands-on, minds-on Today, some 80 years later, flexagons are still stimulating the hands and minds of people around the globe, and connecting fans who share new models and new insights with each other. Enthusiasts manipulate their paper—flexing, not folding—using special movements such as the “pinch flex,” the “reverse-pass through flex,” and the “V flex.” By being both a hands-on and minds-on activity, creating flexagons appeals to adults and children alike, bringing diverse and unlikely groups of people together through their shared affinity for flexagons. This enthusiasm is why the Davidson Institute of Science Education dedicated the first Neil Shore Recreational Math Workshop to the topic of flexagons. The first workshop, held last summer, provided a unique opportunity for some 40 individuals to come together to think, play and learn about flexigons, including researchers, origami artists, educators, and gifted junior-high and high school students to meet, study, and create. American lecturers Ann Schwartz and Scott Sherman, and Dr. Yossi Elran of the Davidson Institute, led the four-day workshop. Art and Science Weizmann MAGAZINE