An interactive rule based system enables problem solutions to be generated in schematic diagram form. A methodology designer selects and arranges graphic primitives using a graphics terminal to create a library of icons. Under control of a computer processor, the methodology designer is prompted to identify, by way example, parameters for using each icon. The system generates and stores a specific set of rules pertaining to the use of each icon on the basis of the parameters identified. The stored rules are cross-referenced to the icon to which they pertain, so that whenever the icon is selected by a problem solving user for use in building a problem solution, the rules pertaining thereto will be accessed and applied. A methodology designer can also select and concatenate functions to each other and to icons to create more complex functions for use in building problem solutions. New functions can also be created in the form of truth tables which establish a transfer function across an icon. By accessing and selecting icons and functions created by a methodology designer, a problem solving user can build a solution to a problem by graphically coupling the icons and functions together on a chart.