The students open their books and start to teach themselves. Perhaps more important, they teach one another. Wijnands walks the room, looking at the Scrum boards and Burndown Charts. Occasionally, he’ll spot a place where the students are having a problem, or he’ll quickly explain a tricky concept, or he’ll randomly take a story from the Klaar column and quiz each student on it, making sure all understand the concepts. If they don’t, he moves it back to Te doen. Part of the Definition of Done, you see, is that everyone understands the material.