Flexagons are folded paper constructions that are fun to flex to reveal hidden pictures.

Tetraflexagons are square. The simplest is the tritetraflexagon, which has three square faces. Hexaflexagons are hexagonal. The simplest is the trihexaflexagon, which has three hexagonal faces. A hexahexaflexagon has six hexagonal faces. The faces appear in different orientations. It is fun to flex a flexagon and try to find all faces in all possible orientations.

Here's a pretty Hexahexaflexagon Pattern (PDF) that I created. The document contains:

The three primary faces each have three configurations. The three secondary faces each have only two reachable configurations. Can you find all 15 configurations by flexing your flexagon?

15 configurations
[Photo by Daniel Eaton]

You can learn a lot more about flexagons at other websites.