Last month I posted a group of photographs documenting flexagons made by fifth grade students. These structures are best seen (and held) to be understood, but, basically, they are a paper toy whose folds, when articulated, reveal hidden surfaces. Got that ? If not, check out Forest of Flexagons. To make a larger copy of the directions shown above here’s the PDF for Flexagon Squared
There are other shapes for flexagon. I also make ones that are hexagon-flexagons, which I like like because its structure can be decorated to mimic fractals. But that’s another story.