 The base of the object meets the plane where the object stands, while the tip of the object is "projected" to a more distant point on the plane.Two projections, one for each eye, are made to produce a pair of images suitable for any dual-image form of stereoscopy (usually anaglyph imaging viewed through colored filter glasses).When the viewer is presented with flat images distorted in this way, the position of points on the image plane matches the points the actual object occupied, producing the illusion.