Motor control in animals, including development of motor control, has an important discrete aspect, even though the mechanics of body movement are well described by continuous mathematics. Physiologically, movement is controlled in large part as transitions between and efforts to remain within discrete spatial regions, such as chair seats and doorways. Based on observations in human development and rehabilitation, this study continues efforts to unify discrete with continuous aspects of motor control. The continuous aspects arise mostly from mechanics; the discrete, from physiology.