Fold a strip of paper and glue the ends together to create a flexagon that displays different images as you turn it "inside out." This, the simplest of the flexagons, is called a trihexaflexagon because it displays three different images in a hexagon. There are a variety of flexagons with different shapes and number of images.
- Print the pattern double-sided and cut out the pattern piece.
- Follow the folding directions printed on the strip: first make a mountain fold where marked, then a valley fold. In the third step, "tuck under," switch positions of the two overlapping triangles; i.e. place the triangle labeled "tuck under" below the other triangle. Finally, fold the protruding triangle over and glue the two faces labeled "glue here" together.
- To use the flexagon, pinch two adjacent triangular faces together and push the opposite edge in.
- With the flexagon pinched together, you can open the flexagon to reveal a new image. If you cannot open the flexagon at this point, repeat the previous step, but pinch two different triangular faces together.
- Repeat steps 3 and 4 until all images are revealed.
Flexagons were discovered by Arthur H. Stone in 1939 when he was a 23 year old graduate student at Princeton University. He trimmed his American-sized paper to fit in his British-sized notebook. He folded the resulting strips of paper and discovered the trihexaflexagon.