Line
There are two definitions of line commonly used in the visual arts.  The first defines a line as a series of adjacent points. When packed tightly together these points appear to form a continuous contour. The second definition describes a line as the movement of a point in space. This definition is useful because it can link points, lines, planes and solids together in a logical way: If you move a point sideways in space and you will create a line. Move the line sideways in space to create a plane. Move this plane sideways one more time to create a solid.