Perspective. Perspective in the graphic arts is an approximate representation, generally on a flat surface, of an image as it is seen by the eye.
   The two most characteristic features of perspective are that objects appear smaller as their distance from the observer increases; and that they are subject to foreshortening, meaning that an object's dimensions along the line of sight appear shorter than its dimensions across the line of sight. Italian Renaissance painters and architects including Filippo Brunelleschi, Masaccio, Paolo Uccello, Piero della Francesca and Luca Pacioli studied linear perspective, wrote treatises on it, and incorporated it into their artworks, thus contributing to the mathematics of art.
   Perspective works by representing the light that passes from a scene through an imaginary rectangle, to the viewer's eye, as if a viewer were looking through a window and painting what is seen directly onto the windowpane. If viewed from the same spot as the windowpane was painted, the painted image would be identical to what was seen through the unpainted window.
   Each painted object in the scene is thus a flat, scaled down version of the object on the other side of the window. Because each portion of the painted object lies on the straight line from the viewer's eye to the equivalent portion of the real object it represents, the viewer sees no difference between the painted scene on
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