Images: Can the Hummer turn over a new leaf?

The Hummer O2 also would use hydrogen fuel--the photosythesis being a separate system meant as a sort of all-encompassing air freshener. The construction in the design uses 100 percent postconsumer recycled materials, including its aluminum frame and seats free of volatile organic compounds. Each of the four wheels houses its own modular and self-contained fuel cell to power a hydraulic motor; the hydrogen tank sits at the center of the vehicle, for safety and structural purposes. The tires, meanwhile, change their shape to suit the terrain.