In that metaphor is made up of ideas and their expression, not just language, it may occur in pictures, not just in verbal representation. Pictorial metaphors for action in line drawings frequently involve events depicted in ways that violate a standard usage of outline and show the course of the action aptly. Metaphorical line pictures may include attempts to depict mental states, such as kinds of perception. Metaphorical pictures depicting perceptual states may be apt, rather than just conventional. That is, they may meet with wide acceptance and agreement on their significance from naive observers, including people who are blind and, therefore, unfamiliar with pictures but have been given the pictures in a raised form. (John Kennedy, Christopher Green and John Vervaeke)