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 the communication between different IOD types.

The primary goal of cybernetics is to control systems. To be able to do that efficiently, one must be able to predict response of the controlled to various input signals. That is why control engineers focus greatly on mathematical modelling as mathematical modelling in practically the only rigorous method to describe system responses.

Control engineers often use block diagrams to graphically illustrate the interactions between modules in a system. Block models considerably simplify the description of a system and make it intuitive. herefore, it is not necessary to describe a system with difficult differential equations etc. We used the advantages of block diagrams to make designing IODs simpler and to make the ideas behind IODs understandable to the non-biologists.