video:  http://www.youtube.com/watch?v=KVRqS4eDxnk
template:  http://loki3.com/flex/ennea.html

I'm continuing my video series on triangle flexagons with the enneaflexagon.  This one has 9 triangles per face and is interesting because the pinch flex only changes 6 of the 9 pats, leading to a sort of kaleidoscope of leaves as you do a series of flexes.  A single pinch flex changes the shape of the flexagon, turning it into a ring.  A second one restores it to an enneagon.

This behavior of the pinch flex also means that it's a bit trickier to travel between sides than with the hexaflexagon.  In the video, I show a sequence of pinch flexes that can get you from sides 1 and 2 to sides 3 and 4.  I also show a sequence of tuck flexes that can accomplish the same thing.

A short word on the flex notation I use for that pinch flex.  Pinch one corner, step 3 vertices to find the next corner to pinch then step 3 more vertices to find the third corner to pinch.  I represent this as P(3,3), where the pair of 3's tell you how many corners to step to find the appropriate vertices to pinch.

Scott Sherman