Single image 3D pics (Magic Eye style)

Have you walked through a mall lately? These days, as you wander past
most of the poster shops, there will be a large group of people
staring at the same poster with surprisingly weird expressions on
their faces. Some will be in the initial stages of denial or
rejection---they will be concentrating, some slowly rocking their
heads backwards and forwards, searching for an image that they have
never seen before. Others will be grinning from ear to ear, pointing
at the poster, chuckling with their friends that a member of their
group hasn't seem them yet.  "Come on Bill, come on!", they cry and as
Bill gets increasingly more frustrated he concentrates harder and
harder, until finally (if he's lucky) he sees a true 3D image, without
the need for special glasses or equipment.

These pictures are known as Single Image Random Dot Stereograms
(SIRDS), or Single Image Stereograms (SIS) depending on whether the
picture contains random dots as a base for the 3D effect, or a
repetitive pattern. Unfortunately, each commercial company has
labelled them differently. Shop owners generally don't know what you
mean, unless you say "Hollusion" or one of the many other specific
names.

(Description from SIRDS-FAQ by Stuart Inglis)

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]               203046  203046 100.0% -lh0- 0df8 Sep  4  1994 spider2.gif
[generic]                  467     873  53.5% -lh5- edb1 Sep  4  1994 spider2.gif.info
[generic]                  226     354  63.8% -lh5- 4f14 Sep  4  1994 spider2.txt
[generic]                32288   32288 100.0% -lh0- 509d Sep  4  1994 spiral.gif
[generic]                  467     873  53.5% -lh5- 8c47 Sep  4  1994 spiral.gif.info
[generic]                32234   32234 100.0% -lh0- 2beb Sep  4  1994 spokes.gif
[generic]                  467     873  53.5% -lh5- 5626 Sep  4  1994 spokes.gif.info
[generic]                51549   51549 100.0% -lh0- d56c Sep  4  1994 stereo1.gif
[generic]                  469     873  53.7% -lh5- 7579 Sep  4  1994 stereo1.gif.info
[generic]                25580  383021   6.7% -lh5- 34d7 Sep  4  1994 stereo1.ps
[generic]               144250  144250 100.0% -lh0- a7bf Sep  4  1994 stereo2.gif
[generic]                  467     873  53.5% -lh5- 150a Sep  4  1994 stereo2.gif.info
[generic]                56404   56404 100.0% -lh0- e285 Sep  4  1994 stereolena.gif
[generic]                  467     873  53.5% -lh5- 335a Sep  4  1994 stereolena.gif.info
[generic]               266414  266414 100.0% -lh0- 06fb Sep  4  1994 tap.gif
[generic]                  467     873  53.5% -lh5- 3acb Sep  4  1994 tap.gif.info
[generic]               191088  191088 100.0% -lh0- 40ae Sep  4  1994 teapot.gif
[generic]                  469     873  53.7% -lh5- 0011 Sep  4  1994 teapot.gif.info
[generic]               104319  104319 100.0% -lh0- 0bde Sep  4  1994 templrds.gif
[generic]                  467     873  53.5% -lh5- 7629 Sep  4  1994 templrds.gif.info
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total        20 files 1111605 1472824  75.5%            Dec  1  1994