Motion parallax as a cue to 
distance and depth: the 
direction of near objects (B) 
changes considerably with 
movement of the observer 
whereas the direction of far 
objects (A) changes little. The 
change in the angular 
direction of the images of two 
or more objects with respect to 
one another (C) can also be a 
cue to depth.

When many objects are visible 
at differing distances, observer 
movement also yields a change 
in the direction of things 
relative to each other, which 
could be a source of depth 
information.