This document discusses visual elements, with a focus on line. It defines visual elements as properties of objects and surfaces that can be observed through sight, though they remain abstract concepts. There are six principal visual elements: point, line, shape, volume, color, and texture. Line is examined in depth, noting that it directs vision, provides structure and underpinning, and has characteristics like being straight, curved, thick, or thin. Lines are also used for systems of notation like letters, maps, music, and schematics. Finally, lines can form patterns.