Whether we consider the parallel rays breaking through the line [math]L_1[/math] in the sky or the convergent rays through [math]L_2[/math] converging towards a "close sun" [math]P[/math], we see that these are indistinguishable when projected on the canvas.[br][br]You can drag the point [math]P[/math] around to see what happens or drag elsewhere to rotate the view.