There are a variety of ways to measure the stretching that occurs when one surface is deformed onto another. Various energies can be defined to quantify such distortions, and the magnitude of these energies can be used to compare the difference between two shapes.
We will discuss some applications of these ideas to mathematics and to biology. In topology, these ideas lead to new results on the space of triangulations of a surface. In biology, we will discuss computations used to compare brain cortices and proteins.