This document discusses the qualities and uses of lines in art. It defines a line as a linear mark made with a pen or brush. Lines can have various qualities like thickness, direction, and texture. Straight, horizontal, vertical, and diagonal lines convey different moods and meanings. Curved lines suggest fluidity and movement while abrupt lines create tension. Overall, lines are used to delineate shapes, control eye movement, provide structure, and enhance comprehension in works of art.