Three hour uninterrupted work cycles enabling deep states of concentration, prepared work for the students and mastery through repetition (deliberate practice). This is Montessori.
From the article, “The secret to continued improvement, it turns out, isn’t the amount of time invested but the quality of that time. It sounds simple and obvious enough, and yet so much of both our formal education and the informal ways in which we go about pursuing success in skill-based fields is built around the premise of sheer time investment. Instead, the factor Ericsson and other psychologists have identified as the main predictor of success is deliberate practice — persistent training to which you give your full concentration rather than just your time, often guided by a skilled expert, coach, or mentor. It’s a qualitative difference in how you pay attention, not a quantitative measure of clocking in the hours.”