Don't know what it costs, don't know what it's made of, don't know even if I can use my standard answer "we promote small space living" to the question "why is this on TreeHugger?," so I will just say it is very pretty. Architect Hayahiko Takese says:
"The Magic Box is a versatile 'box' that changes the stereotypes of prefabricated houses and extension rooms by having qualities such as transparency and simplistic form with high versatility."
"The Magic Box also creates innovative life styles and business environment; You are free to drive your imagination into transforming this box into your own working space or space for your hobbies."
"Magic Box's basic form is a cube structure which can be used in various ways, such as detached living quarters, cottages, stores, offices, cafes, etc. Magic Box provides very modern, cute, and charming space." ::Magic Box via ::Mocoloco and ::Shedworking