Open-ended evolution (OEE) of interacting elementary cellular automata (ECA) was studied by Alyssa Adams et al. (2017). Some instances of composite ECA systems incorporating state-dependent dynamics were shown to satisfy definitions of unbounded evolution (UE) and innovation (INN), facilitating OEE. As an exercise in the rigorous analysis of systems not larger than sufficient to establish universal requirements for OEE, the scope of the study was restricted to small one-dimensional systems (ECAs) in which the perturbation of one subsystem by one other was one-way only (from "environment", e to "organism", o), but the authors recognized that their conclusions should also be relevant to the richer dynamics of large systems of mutually interacting subsystems. In this study, I explore the potential of three mutually interacting hodge podge machines for OEE and recognize that study of OEE in such comparatively large systems is provisionally tractable only by assessment of INN, considered as a reliable UE/OEE indicator.