I remember all the tubes my teacher had in her closet when I was in first grade. The heavy duty tubes look like what you find inside wrapping paper, but they are made from a much stronger cardboard that is as hard as wood.
Designer Seongyong Lee has started designing furniture that reuses this sort of very ridged tube that is often used for mailing things like posters and more. The furniture is very nice looking with wood tops and seats that are finished in different colors.
You have to look hard to see that the furnishings are made from paper tubes. The finished stools look just like they were made from normal wooden poles. This is very green furniture since it reuses stuff that would likely just be thrown away.