A flexagon is an object made out of paper. It is usually in the shape of a hexagon or, less commonly, a square. However, it is not simply a cut-out shape, but instead, a strip of paper (which is not necessarily straight) that has been folded. If one folds the flexagon, they can unfold it a different way and a new face will appear! This "flexing" is what gives flexagons their name. The number of edges on the polygon and the number of faces on the flexagon determine its name. For example, a flexagon with 3 faces and 6 edges (hexagonal) is called a trihexaflexagon. A flexagon with 6 faces and 4 edges (square) is a hexatetraflexagon. There can also be more general names. Any flexagon that has 6 edges, regardless of the number of faces, is simply referred to as a hexaflexagon. A square flexagon is a tetraflexagon. For more information, see the subpages.