These 3 elements are essential to achieving the overall flow of a media piece. The order allows the director to make suggestions about the time period  and chronological order of the clips. Sometimes narratives are linear, beginning at the start and concluding at the end of the narrative, sometimes they are cyclical, when they begin and end at the same point. Other times films jump between past present and future which can create suspense whilst the audience waits for all the ends to be tied and the events to be pieced together. Duration refers to the length of a piece, events can be shown in real time which can create a slower and more subtle effect allowing the audience to notice small details. Directors will also often foreshorten time, this is done as a means of retaining audiences attention and engagement. An example of this would be showing a shot of a person beginning a marathon, then showing a shot of them running along a long road, then showing a shot of them exhausted and reaching their final destination. This way the audience gets an idea of the entire story without having to follow the whole run. Frequency refers to the amount of times a shot is shown, directors can repeat shot to put certain emphasis on one aspect of the film. This reoccurring footage can often portray an internal memory, recollection or nightmare of one of the characters, it can also often be used to foreshadow the future.