An interactive graphical program is described, which uses an object oriented approach for developing conceptual designs. The program is written in the C programming language and designed on a UNIX operating system. It starts with the specifications list, develops function structures and searches for solutions, for systems with mechanical, electrical/electronic, fluid and other components. It can be used for developing new and improving existing devices, systems and processes. Applications include any designs which can be described in terms of interconnected functional blocks with definable input and output parameters. By running the system, the variety of functional blocks can be tested to determine the optimal solution based on the given specifications. Designers will benefit from the pictorial representation; data-based functional and connective representation; and the generation and evaluation of concept variants. The use of the program is illustrated by an industrial design example.