Abstract: A device is described for introducing variation in athletic training and competitive events. This device maintains an internal state that occupies one of several allowed values. Depending upon the selected configuration, the device changes internal state at regular or irregular intervals, progresses through its allowed values sequentially or in random order, and spends a different designated fraction of time in each state. This variable and typically unpredictable state is presented to the field of play where one or more athletes receive the information and react to it as a change in their athletic training or game environment.

Abstract: A device is described which has means to define and maintain different internal states, means to transition at regular or random intervals between those states, means to vary the minimum hold time in each state, means to vary the average time spent in each state, means to vary the order in which the states are visited, and means to externalize and transmit or display the internal state. Subsequently one or more athletes receive this information and react to it as a change in their athletic training or game environment.