We analyze classroom orchestration as a question of usability in which the classroom is the user. Our experiments revealed design features that reduce the global orchestration load. According to our studies in vocational schools, paper-based interfaces have the potential of making educational workflows tangible, i.e. both visible and manipulable. Our studies in university classes converge on minimalism: they reveal the effectiveness o tools that make visible what is invisible but do not analyze, predict or decide for teachers. These studies revealed a third circle of usability. The first circle concerns individual usability (HCI). The second circle is about design for teams (CSCL/CSCW). The third circle raises design choices that impart visibility, reification and minimalism on classroom orchestration. The fact that a CSCL environment allows or not students to look at what the next team is doing (e.g. tabletops versus desktops) illustrates the third circle issues that are important for orchestration.