Other man-made stratified systems can be found in industrial automation, as discussed in Chap. I. A completely automated industrial plant is usually modeled on three strata: the physical processing of material and energy, the control and processing of information, and the economical operation in reference to efficiency and profitability (Fig. 2.3). Notice that on any of these three strata one is dealing with one and the same item, the basic physical product. On the first stratum it is viewed as a physical object to be changed in accordance with the physical laws; on the second stratum it is viewed as a variable to be controlled and manipulated; and on the third stratum it is viewed as an economic commodity. There is a different description, a different model for each of these views of the system; however, the system is, of course, one and the same.