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:

• organize
  by separating or grouping text elements on the page
• texturize
  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
• provide movement
  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
• highlight
  or stress a words
• connect
  pieces of information
• outline
  a photo or set it off from other elements
• create
  a grid / a chart / a graph / a pattern / a rhythm of many lines
• suggest
  an emotion