Remember the first time you saw a Möbius strip (the ring-shaped surface with only one side) and it felt like your world had been turned upside down? The hexaflexagon tends to have a similar effect. Only more so. In this video Vi Hart presents the topologically fascinating hexaflexagon. First discovered in the 1930s by a daydreaming student named Arthur H. Stone, flexagons have attracted the curiosity of great scientists for decades, including Stone's friend and physicist Richard Feynman. Here, Vi Hart introduces the folding, pinching, rotating, multifaceted geometric oddity with her signature brand of rapid-fire wit and exposition. She even shows you how to make your own.