The next set of diagrams highlights the element Line. Unlike point, line has a beginning and end, created by two points. Line is two dimensional. It has no width or depth, only length and thickness. Line can express direction, join, link, outline and define boundries or edges.
Plane defines the next set of diagrams. Plane is a combination of lines that create a two dimensional form. It can be any shape described by negative or positive space.
The next set is all about Volume. Volume is simply plane extended to a three dimensional form. It uses all of the previous elements to exist. It is a solid with mass or a void - volume with no mass.