At a Neighbor's Garage Sale, You Find an Old-Time Stereogram

question 19

Essay

At a neighbor's garage sale, you find an old-time stereogram showing a group of people standing at the center of the Eiffel Tower's base, and a zeppelin hovering in the background. How do the relative positions of the main objects change in the left-eye and right-eye pictures, respectively, to achieve the 3-D effect?

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Definitions:

Iris

The colored part of the eye that controls the size of the pupil and thus the amount of light that enters the eye.

Pupil

The adjustable opening in the center of the eye through which light enters, its size regulated by the iris.

Sclera

The tough, white outer layer (coat) of the eyeball that, along with the cornea, helps to maintain the shape and protect the interior of the eye.

Fovea

is the central area of the retina, where visual acuity is highest.