In most if not all engineering disciplines, engineers design complex systems by combining simpler components. This is the idea of modularity, an idea so potent one could hardly come up example of a functioning system that doesn't use modularity. Why is this idea so fruitful?. Modularity offers easiness of design and simple modification of an already working system. For example, a sensor can be easily replaced by a different sensor to measure different quantity. Same procedure can be done with every other type of component. Diploid IODs form from two haploids. Thus, their user can conduct countless combinations of sensors (receptors), transmitters (pheromones), and locational tags (yeast display). Furthermore, the design of IODS offers another level of modularity in communication between different IOD types.

One of the primary goals of cybernetics is to describe a system, control it, and be able to know the response of this system to a particular input signal. This response may be in the form of an output signal that can be measured and may influence another system. IODs are an excellent example of such modular system. A pheromone represents the input signal, and the output signals are yeast display surface receptors and a different set of pheromones, which are also the input signal for an another IOD part.

Engineers often use graphical block diagramming tools to make the functionality of a system transparent. Block models considerably simplify the description of a system. Therefore, it is not necessary to describe a system with difficult differential equations and recurrence relations. We used these diagrams for a graphical representation of our IODs. This approach made our project clearer to the engineers non-biologists.