Problem solving is an activity that takes place in a rich web of interactions involving people and artifacts. Real-world interactivity was domesticated in a laboratory environment. Participants worked on an insight problem, the so-called 17 Animals problem: the solution involves the spatial arrangements of sets but masquerades as an arithmetic problem. Problem solving took place in two different ecosystems: in one, participants were given a stylus and an electronic tablet to sketch out a model of the solution; in a second, participants could interact with artifacts to build a model of the solution. Participants in the sketch group were never able to break the impasse, whereas model building participants were more likely to propose a correct solution. Video evidence revealed substantial differences in the manner with which participants ‘thought’ about the problem as a function of the type of interactivity. Insight was enacted through model building activity.