Explorable Flexagons: Learn to create and flex flexagons (2020)
loki3.com
loki3.com
[0] https://galeriamonicasaucedo.com/artista/sebastian/66e23dbdc...
The designs are fun, although I find that the thicker paper actually makes them a bit harder to fold and flex than typical printer paper.
If you find flexagons interesting, you might like trying to find a copy of Martin Gardner's "Scientific American Book of Mathematical Puzzles and Diversions" at your local used book sale. The first chapter is about flexagons and it gets better from there! Wonderful car ride, plane, etc. distractions.
https://www.amazon.com/Scientific-American-Mathematical-Puzz...
[1] https://en.wikipedia.org/wiki/Of_Man_and_Manta
[2] before Xanth became his albatross
When I was bored in school, I'd make kaleidocycles (a 3d but less interesting flexagon) with a sheet of paper, a pencil, a ruler, some scissors, and a glue stick. Once I learned Illustrator I began to make some custom printed designed ones.