Elasticity and Geometry: From Hair Curls to the Non-Linear Response of ShellsWe experience elasticity everywhere in daily life: in the straightening or curling of hairs, the irreversible deformations of car bodies after a crash, or the bouncing of elastic balls in ping pong or soccer. The theory of elasticity is essential to the recent developments of applied and fundamental science, such as the bio mechanics of DNA filaments and other macro molecules, and the animation of virtual characters in computer graphics and materials