A line is a mark connecting two points. How we get from point A to point B gives the line its distinctive character and appearance. Lines can be long or short, straight or curved. Lines can be horizontal, vertical, or diagonal. Lines can be solid, dashed, thick, thin, or of variable width. The endings of lines can be ragged, blunt, or curved.
A line is a dot that went for a walk. — Paul Klee
As an element of design, lines can stand alone or be part of another graphic element. They are one of the building blocks of graphic design.
Use lines to:
by separating or grouping text elements on the page
by using specific types of lines to suggest or simulate a rough or smooth texture
guide the eye
by using lines as arrows or in other ways that lead the eye to certain parts of the page
by creating wavy lines that suggest moving water or varying line thickness to create an illusion of shape and movement
make a statement
by using lines with different sizes and contrast
convey universal meanings
by using dashed lines to suggest coupons or wavy lines to suggest water or spirals to suggest a whirlwind of activity
Examples: Used alone, lines can be rules, downrules, or leaders used to separate, organize, emphasize, or provide a framework for the page. Alone or as part of a another graphic element, lines can create patterns, set a mood, provide visual texture, create movement, and define shapes.