The site is located in the island of Hiroshima, Japan. Three sides of the site face the calm environment of Setonaikai Sea. The building is weekend house for 4-person family. The plan has the outline of 4 squares with rotated by a unit of 3 degrees. Its plan leaves the outline which the square from which four sizes differ rotated by a unit of 3 degrees. Each outline is articulated by elements as mass, void, sanitary space, and furniture.

Nested space composition diffuses the gradation of space from a central courtyard - 7.5mx7.5m, and makes the rich continuity in the simple rectangle spaces. Furthermore, a courtyard is extended to the upper private space and developed to the terrace of the north side. By operating with few angles, though a privacy level is adjusted, the open one room is realized. It is the space which can make an excursion, continuing infinitely.