MAN AND COMPUTER can work together on the design of complex components and systems using graphic input/output devices. Man-oriented I/O devices such as light pens, keyboards and displays extend the capabilities of man and computer in evolving a design. Typical design problems include a large volume of data, a profusion of calculations, interrelated decisions, and iterative operations - all readily processed by a computer. These problems also contain creative analytical or job coordination tasks which can be performed best by skilled human specialists. The graphic interface permits “conversational” communication between the specialist (frequently an engineer) and the computing equipment, in the form or a symbolic language having both pictorial and alphameric elements. Such a language is currently the medium for engineering thought, expression and documentation. This closer man-machine rapport allows the computer to aid the designer to aid the computer to perform tasks beyond its preprogrammed capability. This paper describes, in detail, one such graphic application that has been implemented for the design of digital computer circuit cards. References are made to an extended program for the design of complete computing systems.