Cool! I still have a 24-faced hexaflexagon I made in high school (we're talking 1974). I used onionskin paper, and drew the triangle pattern on it with an HP

Cool! I still have a 24-faced hexaflexagon I made in high school (we're talking 1974). I used onionskin paper, and drew the triangle pattern on it with an HP plotter attached to an HP 9830 programmable desktop calculator. (Drawing it by hand with a ruler didn't provide the requisite level of accuracy for such a high-order flexagon.)