Systems thinking means understanding a system by examining the linkages and interactions between the elements that compose the entirety of the system. In systems thinking, the structure of the system is mapped or diagramed using the language and visual images of "stocks" and "flows." Stocks represent accumulations of information, material, or psychological states that build up or diminish over time through the actions of flows. Flows are the "filling or draining" process that change the amount of stock over time.