ABSTRACT
A flat piece of paper is malleable. We may define its extrinsic geometry by bending and folding, without stretching, tearing or deforming its surface. Its intrinsic geometry does not change. An intrinsic property is an inherent property of the paper. For example, a straight line drawn on a paper is intrinsically straight, although the line in 3D space is extrinsically not straight when you bend the paper.
