Artifacts not intended to represent but displaying agreed-upon graphic symbols. Examples are signals, signs, ideographs, alphabetic letters, numbers, writing. Invented structures . Artifacts not intended to represent anything nor to employ graphic conventions but only to display the possibilities of optical structure as such, considered as stimulation independent of its source. As opportunity for pure discrimination, this interests both artists and psychologist.
Examples are decorations, design, mathematical construction, modern paintings.
Simple or complex repetitive or lawful patterns. Used either to embellish other objectives or simply to be looked at. This includes man generated randomness of pattern or texture or, recently, computer-generated randomness. The perceptions induced are curious and puzzling. The study of optical texture as stimulus information for visual perception should be pursued from two directions, both for out understanding of the perception and identification of environmental surfaces and for an understanding of the visual discriminative process as such.