When I posted briefly about Yama Yamauchi’s fireworks model, which is a flexible origami model that looks much like fireworks do, I neglected to include the link to the folding pattern. Yama Yamauchi in fact has a whole set of web pages with patterns, that can be reached from Yami’s Corner.
But that sends you down the rabbit hole to find other flexagons, such as the tutorial at Flexagon Instructions.
And there goes my work day …