Suggest some designs that can be a contest for 3rd year college students. The materials that will be used are recycled as much as possible. For example, a mouse trap car.
I'm building a shop out of cast concrete pieces and 8'' schedule 80 pvc pipe donated by the city after their recent water service expansions. I'm casting all the concrete pieces myself and the pipe will serve as support columns for the roof. and everything can be shipped on a flatbed tractor trailer. it 12'x12' with a 9' roof and an r-value of 70 with a fire rating of 1 hr since it is made mostly of concrete.