Most of us learned about perspective in grade school. The visual perspective that we learned about, with at least one vanishing point, was not really figured out until the Middle Ages. Until then, the only way of indicating distance in a painting was to use "atmospheric" perspective, that is, putting things farther away in more of a haze; overlapping was utilized also. Images closer to the viewer obscured, to some extent, those farther back. The lack of understanding that children have of this concept can be seen easily in their depiction of "x-ray" images... ones you can see through to know what is behind. The newer views done with computer-assisted drawing do not have the capability of showing vanishing point perspective, so look oddly wrong to us. Vanishing point perspective is the view we get when we look down a railroad track toward the horizon, and see the tracks appearing to merge in the far distance, although the tracks are parallel.