Each environment is designed to meet the needs, interests, and abilities of the children within the class. Guides adapt the environment by modifying the selection of educational materials available, the physical layout and equipment in the classroom, and by shifting the tone of the class to fit the ever-changing needs of the children. Generally, students work individually or in small self-selected groups. Community meetings or “group times” are scheduled so as not to interrupt the child’s work and are usually held at transitional points during the day.