OnSugar blog Think Magazine recently shared the Rebound Chair designed by industrial designer Andrea Hardcastle, which is an eco-friendly piece of furniture. She writes, "It can stack quite easily and weighs in at a meager 15lbs. As fragile as they may look they're very durable and can be used outside." The frame is made out of recycled steel, but the seat and backrest are made out of something you'll find on roads all across the country. Can you guess what material it's made out of?