-Robert McGuigan, Mathematical Association of America, 2004
"Flexagons were discovered in 1939 by Arthur H. Stone, then a graduate student at Princeton. Coming to Princeton from England, Stone found that the standard notebook paper in the United States was about an inch too large for his British binder so he trimmed the paper to fit and had many strips of paper as a result. Playing at folding these, he folded a strip diagonally three times and joined the ends so that a hexagon consisting of six triangles was formed. When two adjacent triangles were pinched together and the opposite corner pushed toward the center, "flexing" the figure, the hexagon would open out and show a completely new face. Stone showed his discovery to friends at Princeton, and this led to something of a fad."