Here's a data flow model diagram. A data flow diagram (DFD) depicts the information flow for any process or system. It shows data inputs, outputs, storage sites, and the pathways between each destination using predetermined symbols such as rectangles, circles, and arrows, as well as brief text labels. Data flowcharts can range from simple, even hand-drawn, process overviews to detailed, multi-level DFDs that delve progressively deeper into how data is processed. They can be used to examine a current system or to create a new one. A DFD, like all the greatest diagrams and charts, can frequently graphically "express" things that are difficult to describe in words, and they work for both technical and nontechnical audiences, from developer to CEO.