One system that I encounter daily is that of a neighborhood supermarket. The purpose of a neighborhood supermarket is to provide sustenance to the surrounding residents. In addition to this purpose, it could also serve the purpose of a social gathering place, or a money making enterprise for its owner.
The parts of this system include the employees, the location, the furniture and shelving used to maximize the efficiency of this system, the customers who visit this system, the grocery suppliers and the power and water grid that further supply this system. One could say that this system has even more indirect parts, such as the families of the customers and the farmers who produce the groceries. The greatest inflow in this system is the grocery suppliers, which deliver food to the supermarket on a regular basis. The greatest outflow in this system is the customers, who purchase the groceries and take them out of the supermarket. Ideally, the system is self sustaining.Overall, this would look like consumers purchasing the groceries that they want, the supermarket taking their money and ordering more food so that it can continue to provide the groceries that the consumers want.
I would imagine that most of the feedback in a supermarket is data-driven. For example, if a new study shows that coconut water contains carcinogens, then presumably people would not want this product. The supermarket manager would note a sudden decrease in demand for coconut water and they would reduce the inflow of that product by ordering less of it. On the other hand, as a food item becomes popular, the manager would presumably order more of it. One challenge of a supermarket manager would be to keep just enough product in stock to sell without having any of it expire. This is likely what dictates most of the feedback within the ordering and selling systems of a grocery store. One way a manager could control sales is by lowering the price of perishables that are soon to expire.
To sustain the behavior of a supermarket, a system of cataloging what is purchased in what quantity must be maintained. Presumably, this is handled digitally, using barcode-driven sales data. Once a system alerts a manager to a diminishing number of products, they will presumably place a new order for those products. They will use some fraction of the money that the consumer paid them to pay the product supplier, thereby bringing the consumers more of the products that they have been purchasing.
