This is a proposal for a future dwelling, which can accommodate two residents and two guests. There is no height limitation but the maximum gross floor area is 15m². This number is derived from J.G. Ballard's science fiction novel, "Billenium." In the novel, the population of the earthreaches 20 billion and 95% of the population resides in cities. Residential floor area per person is limited to 4m² in that world. Although the total area should be 16m² if it is for 4 people, 15m² is determined by a new area regulation - 3.5 m² in the novel. This theme is inspired by the fact that a 4-seat super mini car from India’s Tata motors leaped into the market with the surprisingly low price of US$200.