A new line of development was opened by Frank B. Gilbreth, one of Taylor’s most prominent followers. He added to time study the concept of motion study: that is, the investigation and classification of the basic motions of the body, regardless of the particular and concrete form of the labor in which these motions are used. In motion and time study, the elementary movements were visualized as the building blocks of every work activity; they were called, in a variant of Gilbreth’s name spelled backward, therbligs. To the stopwatch were added the chronocyclegraph (a photograph of the workplace with motion paths superimposed), stroboscopic pictures (made by keeping the camera lens open to show changing positions assumed by the worker), and the motion picture; these were to be supplemented by more advanced means. In its first form, motion study catalogs the various movements of the body as standard data, with the aim of determining time requirements and making the procedure “primarily a statistical problem rather than a problem of observation and measurement of particular workers.”