Modeling a logic design includes displaying a menu comprised of different types of functional block diagrams, receiving an input selecting one of the different types of functional block diagrams, retrieving a selected functional block diagram, and creating a graphical representation of a logic design using the selected functional block diagram. The graphical representation is created by interconnecting the selected functional block diagram with one or more other functional block diagrams to generate a model of a logic design and defining the selected functional block diagram using simulation code if the functional block diagram is undefined when retrieved.