well, maybe i wrote it wrong.. of course it is a concept, as i previously read, and mike explained based on mutual communication between kids. i am not saying that this is way of constructing building, but concept of spending time does affect how the building is done, too. so, i heard just about this one, but cannot find more info about it... and i am sure there is lots of different concepts about preschool education around the world.
so, i was just thinking that maybe somebody here knows more about this (not just tsutaeai, but other systems, too) part of education in Japan..