>>> Hank Simon wrote: The traditional flapping bird generates a curved surface >>> by tension.
>>> Cheng Chit answered: How does this come about? Since all the creases are >>> straight. The model is basically flat or can be flatten. I wasn't complete. When I pull the neck to flap the wings, that generates a curved surface. What I wanted to know in general, have you, Cheng Chit, or anyone generated a paper about how to do this with straight lines? Winnie Leung pointed to your categorizations: http://www.flickr.com/photos/chengchit/920470628/in/photostream but I couldn't tell if this was a list of the shapes, or a discussion? - Hank Simon
