In the past, a tube was considered a piece of metal.
But now glass is used to form the inside of an object.
It is known as a spiral tube.
The glass tube is usually made from a material called glass, but there are many other types of glass.
Some are made of carbon fiber, which is lighter than steel and is often used to make light-colored objects like sunglasses.
Other types of plastic are often used for the glass tubes.
The tube is often cut into pieces, called spiral pieces, and the plastic is used as a covering.
There are other uses for plastic, too.
Plastic is used for containers, including a kitchen sink.
Some scientists believe that a plastic tube can also be used to create new materials.
These include a metal tube, a spiral-shaped object called a spiral ring, and a thin, flexible tube.
