In the triangle of coins problem coins are arranged to create a triangle pointing down and the solution involves moving a few coins to change its orientation. The task ecology can be designed such that participants can work on it in a low interactivity environment, maintaining a mental representation of simulated moves, or in a high interactivity environment, thinking with and through a physical model of the problem. These task ecologies involve working memory to a different degree: Problem solving draws more on working memory the lower the degree of physical interaction. Participants first engaged in a writing task that required vigilance to inhibit common word choices, a degree of self regulation designed to induce a so-called ego depletion; participants then worked on the ToC problem in either a low or high interactivity environment. Solution rates were determined by level of interactivity; the preceding depletion experience did not impact performance.