Perspective (graphical) on the horizon line. All lines parallel with the viewer's line of sight recede to the horizon towards this vanishing point. This is the standard "receding railroad tracks" phenomenon. A two-point drawing would have lines parallel to two different angles. Any number of vanishing points are possible in a drawing, one for each set of parallel lines that are at an angle relative to the plane of the drawing. Perspectives consisting of many parallel lines are observed most often when drawing architecture (architecture frequently uses lines parallel to the x, y, and z axes). Because it is rare to have
Point plotting |"x"| from the origin and along the positive direction if "x"≥0, and the other direction otherwise. In the same way one picks the point on the "y" axis corresponding to the number "y". The line parallel to the "y" axis going through the first point and the line parallel to the "x" axis going through the second point will intersect at precisely one point, which will be called the point with coordinates ("x", "y"). Point plotting Point plotting is an elementary mathematical skill required in analytic geometry. Invented by René Descartes and originally used to locate positions on military maps,