The "open classroom" system of child-centered education is sometimes confused with Montessori. The term itself is somewhat imprecise. Roughly speaking, it means a break with traditional methods of wholeclass "chalk and talk" teaching, and the adoption of a more elastic educational program, more adapted to the needs of children. Some open classrooms reject every rule set in advance and let children learn what they like, when they like, and only if they like, with the implication that some children may not learn anything at all. In some others, the "openness" consists merely of having no walls between classes, but otherwise pursuing the conventional type of same-for-all collective lessons.