In this paper we consider about the structure of an intelligent computer-aided control systems design (CACSD) based on object-oriented language. We also indicate a frame in which the controlled system is a receiver and the control design is a message. From this view we construct the extended feedback structure of a design process. The graphics produced by object-oriented language is important for designing control systems, because it is concerning with the characteristics of a control system but also presenting the structure of a control. We point out that the graphics or the symbols are treated as input and output patterns produced from the design process. It is displayed as a complex potential which is an extended form of the Bode diagram. The complex function expresses a control structure as the transformation of a transfer function. Finally We explain a graphic data-base for intelligent control systems design and a human fuzziness which is transferred into the computer through graphics or symbols.