It is sometimes required to record in minute detail the simultaneous movement of the different parts of the body of an operator during the performance of a single cycle of operation the cycle time of which is very small. This is done with the help of a SIMO( simultaneous Motion Cycle ) chart . it is a two handed process chart on a common time scale designed to fulfil the function. If the movements are so fast that the naked eye of the operator cannot follow them a cine camera is employed to film the work. The film is then analyzed by projecting it as slowly as desired and recording on a common time scale the simultaneous and specific diversions of movements performed by the operator. While recording it makes use of the therblig symbol which represent the elementary movements of human activity.