Playing with Stereograms
Stereograms are used to help visualize mathematical objects and constructions.
This stereogram applet is very large, so it opens in another browser window.
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Click here for the stereogram applet.
What is a stereogram? A stereogram is a two dimensional (flat) picture which, if
viewed properly, gives the impression of three dimensional (3D) space.
A stereogram uses the same principles as our eyes do to get a 3D impression of an
object. For example, when you look at a tree, it doesn't appear to be flat,
but appears to have depth within the space in which it stands -- it's 3D. Looking at a
tree, two pictures appear on the retina of your eyes, one picture on each
eye. Each picture is two-dimensional, but the tree looks like its actual
3D reality. This phenemon happens because the two
pictures on your eyes aren't identical. The difference in the pictures
is caused by the placement of our eyes. An adult has approximately 7 cm between
the eyes. If you're looking at an object ten feet away, for example, the
direction of our eyes isn't parallel, but is actually at an angle. The angle
depends on a distance of the point we're viewing. Only as we look towards
infinity will the direction of our eyes become parallel. The angle between
the direction of our eyes is crucial for 3D perception. The stereogram measures
these angles for you.
To view the stereogram applet, focus behind the picture to make the angle smaller
than the one you get if you focus on the picture itself. If you keep focusing
behind the picture, the points on the stereogram will start to fuse - and you'll
see the 3D impression of the image. Enjoy!
More Math & Science Fun
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Thanks to Borut Jurcic Zlobec for the Stereogram applet.