Fuji Kindergarten (aka The Roof House) Tachikawa, Tokyo, Japan. The building which is shaped like a giant halo, has no inner walls, no dead ends, no outer walls. Inside space has been partitioned by racks and full sized sliding glass replaces outer walls on the inner and outer rings. The no-barrier concept not only allows total freedom to kids to move and mingle around but also provides free access to the inner and outer playgrounds. Even the roof is easily accessible and has slides.