The common housefly is a marvel of aeronautical engineering. One reason the fly is a master at evading the handheld swatter is that its wings beat remarkably fast—about 200 times a second. To achieve this amazing speed, the fly makes use of complex biomechanics. Its wings are not directly attached to the muscles of the thorax. Rather the fly tenses and relaxes the muscles in rhythmic cycles that cause the thorax itself to change shape. That deformation in turn sets the wings to oscillating, much the way a tuning fork vibrates after having been struck. In this way, the fly manages to convert a tiny bit of energy into a whole lot of motion with very little effort.