This great website better elucidates the concept.
We have also explored the concepts of line, shape, form and space. Students were given the following list and asked to illustrate the emotions using line:
Angry
Ecstatic
Sensual
Assertive
Feminine
Childish
Masculine
Somber
Lonely
Hesitant
Line is the term given to the extension of a point in space.
Shape is the definition of space by enclosing it with line.
Form is what the shape describes.
Space is the 2 dimensional or 3 dimensional expanse in which objects exist or are placed.