In certain digital environments, "hot-spots" are key infrastructural pieces that allow the dynamic construction and re-construction of mathematical figures. We shall discuss their existence with respect to what we call user-environment co-actions, describing how they are sustainable bi-directional processes that have the potential to ground and develop mathematical concepts. Users are actively changing the status of the object of inquiry through the executability of the environment. These forms of co-action make feasible the enhancement of the framework of instrumental genesis to accommodate the changing form of technology, in particular, the changing actions of the users. We conclude that the space of the learning environment dynamically changes to be one where we can stretch the limits of the tools or artifacts of our environment and hence drive the Zone of Proximal Development of the Artifact (ZPDA) itself through co-action.