I like to watch people try to reach up and touch the rotating cube in the Stereoscopic Depth-Analysis screening room with a 14 ft wide screen.
The cube has from 2.8% to 3.8% net deviation throughout this entire animation, which not coincidentally is the definition of the range of depth in a stereoscopic image that produces a perfectly cubic stereoscopic illusion, viewable with any horizontal field of view (from any seat).
Here’s an up close and personal look at the stereoscopic cubic illusion. Although you can’t see the entire cube, the stereoscopic calculations for the cubic illusion are still, as always, the same.
3.3% (1/30) Stereoscopic Net Deviation is the only amount of depth that can produce a perfectly cubic stereoscopic illusion, viewable with any horizontal field of view (from any seat).
Watch this video in 2D or 3D by clicking on the “3D” button under the video and selecting your options, e.g., “Turn off 3D”.
If you are using red/cyan anaglyph glasses, be sure to select “Red/Cyan” then “Optimized (Dubois)”.
Here’s three numbers you might want to memorize for when you go watch a 3D movie at a movie theater or watch one on your 3D TV.
These are some very relative numbers, if you want to squeeze a stretched-out stereoscopic cube back into a cubic illusion, or if you would like to attempt to squeeze some poorly created 3D with too much depth back into a familiar shape by moving closer to the image:
If you sit 2x the image width away from the screen or TV, the horizontal field of view, which is measured from an imaginary “monoscopic eye” in the middle of your real, two eyes, is close to 28 degrees.
If you sit 1x the image width away from the screen or TV, the horizontal field of view is close to 53 degrees.
If you sit .5x the image width away from the screen or TV, the horizontal field of view is close to 90 degrees.
BTW, a 33.3 degree horizontal field of view is close to 1.66x away from the screen or TV.
3.3% (1/30) Stereoscopic Net Deviation is the only amount of depth that can produce a perfectly cubic stereoscopic illusion, viewable with any horizontal field of view (from any seat).
Look at the first shot in this stereoscopic cubic illusion of a cube with a 33 degree horizontal field of view (hFOV).
Move progressively closer to the image for the following shots to match the hFOV amounts that are needed to squeeze the depth of the cube back into a cubic illusion.
Not coincidentally, 4.4% NetD requires a 44 deg hFOV, 5.5% NetD requires a 55 deg hFOV, etc. Our human binocular hFOV is limited to about 100 degrees, so the final shot will require getting close enough to the image to fill up our entire hFOV.
3.3% (1/30) Stereoscopic Net Deviation is the only amount of depth that can produce a perfectly cubic stereoscopic illusion, viewable with any horizontal field of view (from any seat).
Watch this video in 2D or 3D by clicking on the “3D” button under the video and selecting your options, e.g., “Turn off 3D”.
If you are using red/cyan anaglyph glasses, be sure to select “Red/Cyan” then “Optimized (Dubois)”.
Although the stereoscopic illusion is cubic, it applies to any shape, object or scene, not just a “cube”.
This is a good thing, since monitors, TV’s and movie theater screens are usually rectangular. 
From “Flat” to “Cubic”.
Back to square one with the Stereoscopic Cubic Illusion.
A 45 degree Z-axis rotation of a square, followed by a 45 degree Z-axis rotation of a rectangle.
The 45 degree Z-axis rotations of this square and cube introduces very close to 3.3% (1/30) Stereoscopic Net Deviation, which is the only amount of depth that can produce a perfectly cubic stereoscopic illusion, viewable with any horizontal field of view (from any seat).
Watch this video in 2D or 3D by clicking on the “3D” button under the video and selecting your options, e.g., “Turn off 3D”.
If you are using red/cyan anaglyph glasses, be sure to select “Red/Cyan” then “Optimized (Dubois)”.