Growing up, before the internet, I fell in love with libraries. I discovered Scientific American and it's regular column "Mathematical Games" by Martin Gardner. I eventually read every one of those columns written by Gardner and picked up a lot of science from the rest of the magazine along the way. When I discovered his 1950's column on hexaflexagons I introduced them at my junior high school where dozens of us carried them around and played with them at lunchtime. Several other diversions I learned from Martin Gardner also made the rounds at that school.
I highly recommend the Mathematical Games columns written by Gardner; many of the more interesting ones are available in his books as collections, for example [1], which is less than $5 on Amazon. (Equally fascinating to me then was the Scientific American column "Amateur Scientist", this went back decades farther than "Mathematical Games" and showed projects, actually built by readers, that were often completely over the top--atom smashers, x-ray machines, sophisticated seismographs, etc. Thank goodness I didn't kill myself in my homemade lab in the basement.)
For an up to date treatment of the flexigon see [2].
[1] My Best Mathematical and Logic Puzzles, Martin Gardner, Dover, 1994.
[2] Flexagons Inside Out, Les Pook, Cambridge Univ Press, 2003.
This is one of these things I feel a lot of hackers might know already but I only discovered them yesterday :)
When playing a nice pen and paper roleplaying game of Cthulhu, our GM had us trapped in a non-euclidean manor where the doors through which you went changed the configuration of the space. We had an insane clock device with us (in the shape of a symbol-ridden hexaflexagon as a playing aid on the table) that allowed us to eventually navigate through the thing.
The only catch was none of the players had ever heard of hexaflexagons and the GM flexed the device hidden from view. So we did an unspeakable amount of diagrams trying to figure out how the device might work. Good times.
Anyway, this is awesome and everybody should know about them.
I highly recommend the Mathematical Games columns written by Gardner; many of the more interesting ones are available in his books as collections, for example [1], which is less than $5 on Amazon. (Equally fascinating to me then was the Scientific American column "Amateur Scientist", this went back decades farther than "Mathematical Games" and showed projects, actually built by readers, that were often completely over the top--atom smashers, x-ray machines, sophisticated seismographs, etc. Thank goodness I didn't kill myself in my homemade lab in the basement.)
For an up to date treatment of the flexigon see [2].
[1] My Best Mathematical and Logic Puzzles, Martin Gardner, Dover, 1994. [2] Flexagons Inside Out, Les Pook, Cambridge Univ Press, 2003.