Flexagons. Paper polygons that are able to reveal and hide. Paper shapes able to transform. Paper polygons… the possibilities are endless.
Flexagons were invented by British student Arthur Stone in 1939. He just moved from England and is studying at Princeton University, to find out that his new (American) notebook paper dosen’t fit in his old English binder. So he cut off the edges and started playing with the strips, which one of them made a Trihexaflexagon(with 3 sides). This was made by folding the strip into triangles and then a hexagon shape. The next day, he found out that if you rolled a strip with 19 triangles into a coil and folded it up, you would get one that had six faces, which was named the hexahexaflexagon.
A few days later, some of his fellow students(Bryant Tuckerman, Richard Feynman, and John Tukey) got interested and formed the Princeton Flexagon Committee. After seeing a hexahexaflexagon reveal more colors than he expected, Tuckerman devised a way(called the Tuckerman Traverse) to reveal the 6 faces. Feynman later maps out the traverse.
Things get popular until 1941(WWII), when flexagons are nearly forgotten. Luckily, 15 years later, a mathematician named Martin Gardner gets shown a flexagon. He gets intrigued and writes an article for Scientific American, and flexagons become basically immortalized.
And the rest is just history.