Utilization of a numerically controlled machine for marking and cutting steel plates involves the necessity of adopting some system of “nesting”, that is, of geometrically arranging the various pieces to be cut out from a given material plate, and to present the resulting arrangement in a form suitable as input data for manipulating the particular NC machine to be used. Two kinds of nesting system are in current use- (a) by card and (b) by graphic display apparatus. With the card system, the designer works out the nesting plan manually, using cutout card patterns. that he arranges by eye on a framed sheet representing the edges of the material plate. The resulting arrangement is then translated into digital input data by visually reading out the coordinates that represent the patterns in their nested positions. The output from the machine is produced by drafter or plotter in visible form for purposes of checking, as well as in the form of taped digital data for use in the NC machine. The graphic system, on the other hand, utilizes an optical screen for both input and graphic display. Both systems have their merits and shortcomings. It is an established fact that digital computers are not suited to treating analog information. The human eye is far more adapted to this kind of operation. On the other hand, these computers possess a large capability for calculation, once the information has been digitalized. The basic principle underlying the CADS NESTING SYSTEM is to divide the functions between man and machine in such manner that each performs the operations to which each is best suited, i. e., the designer entrusted with the decisions involving patterns and pattern arrangement, and the machine with the calculations required to evalutate the arrangement worked out by the designer. In line with this principle, the system has been devised to permit the designer to “converse” with the machine by means of a variety of “commands” each embodying a simple instruction for the computer to perform a certain function.