Size: 238 sq. ft.

Location: San Francisco, California

The rEvolve was developed as part of a housing competition organized by the Sacramento Municipal Utility District, and made by a team of students at Santa Clara University. It cost $86,000 to build, with $25,000 of that cost going toward a tracking ring that rotates the structure to face the sun.

It's surprisingly roomy, and features eight 330-watt solar panels on the roof for solar power.

There aren't plans to build more of them, but the rEvolve prototype was donated to Operation Freedom Paws, which pairs service dogs with disabled veterans who need them, and is used as temporary housing for veterans who visit the Bay Area.