This video shows how two curved beams can interact to produce bistability. The green and blue beams are constrained so that their tips stay a fixed distance apart, shown by the red dotted lines. (In practice, the red line would be another beam made out of the same material.) The green and blue beams also have a preferred radius of curvature that minimizes their stored energy. We adjust the preferred radius of the blue beam by changing the temperature. However, the constraint makes it impossible for the green beam to take on the preferred radius of curvature at the same time. Instead, there are two mirror-image energy-minimizing states. In the video, the beams are drawn thicker when in the energy-minimizing state; at the same time, the slider on the energy plot is at a local minimum.