In this note we present a pedagogical approach of variable interactions applied to a 2×2 MIMO system and its confrontation to acquired data from a combined cycle power plant, is studied. The Laplace space is used as a scenario to compute basic operations and subsequently the resulting relations are transformed in convolution integrals. The term responsible of interaction is then simulated and confronted to acquired data from dynamics variable of the power plant. Concretely, attention is paid to the drum level which turns out to be the variable of most importance inside the combined cycle power plant. Our approach is as a pedagogical introduction with a theoretical model sustained even for those cases where the temporal evolution of the drum level is notably affected by intrinsic fluctuations. Thus, a discrepancy between model and data results to be of order of 5%. It would suggest that the interaction variable formalism might be of interest to design model-based control theories which could be applied to those MIMO systems which are plagued of intrinsic and stochastic fluctuations.