I have a great idea for a startup which bioengineers a solar-powered carbon capture system. These systems would capture carbon and embed it in cellulose. That cellulose could then be used for a variety of purposes: as a building material, fuel source, etc.

We could engineer these systems to be very aesthetically pleasing, with colorful 'leaves' and various types of cellulose layers of different colors and hardness. They'd be useful as shade structures, and they could also have other uses such as preventing soil erosion.