Asimple industrial robot has four axes of motion, controlled by four separate motors. we will refer to the motions as turn" (right or left), "lif" (raise or lower), "extend" (in or out), and grip" (contract or release). when the robot is programmed to perform a task, a sequence of these motions will take place. for example, to pick up an object, the arm would turn to align with the object, extend to reach it, grip it, and lift. we are interested in predicting how the actions will occur, in order to accelerate the controlling software. if, for example, a turn is most likely to be fol- lowed by an extension, the code that controls the extension can be readied in advance. from a sam ple of robot programs, representing a set of typical tasks, the following count data was derived: 90 20 20 30 15 80 40 50 30 15 40 15