Hi, I have a problem that I'm trying to solve and I'm not sure at all how can I proceed. If we have a metal rectangle (or maybe a rectangle-shaped hole in a piece metal), and we stretch this body a small distance, what is the shape of the top and bottom lines of the body? Can we say it is a catenary? A parabole? Can anyone lead to me to some good papers or books in the subject? Thank in advance.