Addictive and easy to print, it's everyone's favorite math toy!
It's by far the best printed-in-place toy I've encountered.
I made my own Trihexaflexagon after all my attempts to print whpthomas' model were unsatisfactory, in terms of opening without breaking and flexing without effort. I use an Ultimaker2 and I tried customizing the tolerance up to 0.55 but in vain...
I hope this helps. If you make one, please share the pics!!! :)
The original, of course, remains GREAT WORK.
Vid: https://youtu.be/jaIunj31xCE Original: http://www.thingiverse.com/thing:141124 About hexaflexagons: https://youtu.be/VIVIegSt81k