Length and width are two important dimensions in the world of art. Artists that work with only these two dimensions must add depth through perspective. An artist that draws will have a perspective point within their work. All of the objects they draw will be in relation to this perspective point to provide depth to their drawing. Without it, the drawing will look primitive. Primitive artists had not quite figured out how to include depth in their works.
Painters are another group that deals with perspective points to give their art a perception of depth. They use the same technique to add perspective. Other artists that use this technique are those that work with leather and wood burning. They create a design or picture with little or no physical depth. Some woodworkers create scenes that are relatively flat as well. While they have the option of creating depth within their piece, many use the surface only.