Most materials are elastically anisotropic. In other words, their stiffness depends on the direction in which the stress is applied. This Demonstration illustrates the anisotropy of many cubic metals. The plot on the left shows the elastic modulus as a function of direction in 3D space, while the plot on the right shows a section through the 3D plot in the plane. The anisotropy factor, , is determined by where , and are elastic constants of the materials.