Origami is the Japanese art of paper folding. When I was a kid, we were always making fortune tellers like the one in the video below.
Check out these Google images to see a wide array of origami. In addition, here’s a great gallery and instructions for Modular Origami, my favorite kind. See the Kusudama ball I made below.
Origami Kusudama Ball and Photograph by Keri Valentine
Wikipedia writes about the mathematical and practical applications of origami. Before clicking on the link, try to think of how origami might be used in these ways.
Please make suggestions for how I might revise to help Google recognize this page when people search for mathematics+origami (also search terms like geometry, mathematization, etc.). Thank you, Keri.