What is a geoboard made of?

A geoboard is a mathematical manipulative used to explore basic concepts in plane geometry such as perimeter, area and the characteristics of triangles and other polygons. It consists of a physical board with a certain number of nails half driven in, around which are wrapped geo bands that are made of rubber. Normal rubber bands can also be used. Geoboards were invented and popularized in the 1950s by Egyptian mathematician Caleb Gattegno (1911-1988).[1]

A geoboard is made of a physical board, some nails, and geo bands that could be rubber bands.