While we're on the subject, I will add a bit to the criticism that Communist started here by attacking how Rowbotham deals with vanishing points (which I've done before briefly but was ignored).

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From ENaG:

A very good illustration of the difference is given in fig. 76. False or prevailing perspective would bring the lines A, B, and C, D, to the same point H; but the true or natural perspective brings the line A, B, to the point W, because there and there only does A, W, E, become the same angle as C, H, E. It must be the same angle or it is not the vanishing point.

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Lord have mercy, what a load of crap. The angles Rowbotham describes arise simply as a result of how we perceive the world. A,W,E must not be the same angle as C,H,E for it to be the true vanishing point. Not even close. A,B and C,D must indeed converge at the same point H, and A,B will approach this point at a greater angle because it is farther away from the eye-line than C,D. The fact that our eyes percieve this to be the case is what allows us to perceive depth correctly and to judge our spatial position with respect to other objects accuratelly. If you look at a picture I've labelled:

You can clearly see that the line A (which is farther away from the eye-line) will converge at the vanishing point (H) at a greater angle than the line C. This is to be EXPECTED. It is how we accuratelly perceive the world. In fact only lines which are equidistant from the eye-line will approach the vanishing point at the same angle. All other lines will approach at different angles and rightly so, else the world would appear radically different.