ASCII stereogram

ASCII stereograms are a form of ASCII art based on stereograms to produce the optical illusion of a three-dimensional image by crossing the eyes appropriately using a single image or a pair of images next to each other.

To obtain the 3D effect (in Figure 1 for instance), it is necessary for the viewer to diverge their eyes such that two adjacent letters in the same row come together (). To help in focusing, try to make the two capital Os at the top look like three. Ensure that the image of the central dot is stable and in focus. Once this has been done, look down at the rest of the image and the 3D effect should become apparent. If the Os at the bottom of Figure 1 look like three, then the effect is reversed. It is also possible to obtain opposite 3D effects by crossing the eyes rather than diverging them ().

Figure 1: Near and far distances.

                             O    O
n   n   n   n   n   n   n   n   n   n   n   n   n   n   n   n   n
f    f    f    f    f    f    f    f    f    f    f    f    f    f
e   e   e   e   e   e   e   e   e   e   e   e   e   e   e   e   e
a    a    a    a    a    a    a    a    a    a    a    a    a    a
a   a   a   a   a   a   a   a   a   a   a   a   a   a   a   a   a
r    r    r    r    r    r    r    r    r    r    r    r    r    r
r   r   r   r   r   r   r   r   r   r   r   r   r   r   r   r   r
                            O       O

Figure 2 demonstrates the effect even more dramatically. Once the 3D image effect has been achieved (), moving the viewer's head away from the screen increases the stereo effect even more. Moving horizontally and vertically a little also produces interesting effects.

Figure 3 shows a Single Image Random Text Stereogram (SIRTS) based on the same idea as a Single Image Random Dot Stereogram (SIRDS). The word "Hi" in relief can be seen when the image clicks into place. ()

Some people have included stereograms in their "signature" at the end of electronic mail messages and news articles. Figure 4 is such an example.

Figure 2: A floor, wall and ceiling.

                           O          O
.  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
 .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .
   .    .    .    .    .    .    .    .    .    .    .    .    .
   .     .     .     .     .     .     .     .     .     .     .
     .      .      .      .      .      .      .      .      .
 .       .       .       .       .       .       .       .       .
      .        .        .        .        .        .        .
   .         .         .         .         .         .         .
.          .          .          .          .          .          .
|          |          |          |          |          |          |
|          |          |          |          |          |          |
|          |          |          |          |          |          |
|          |          |          |          |          |          |
|          |          |          |          |          |          |
|          |          |          |          |          |          |
   .         .         .         .         .         .         .
      .        .        .        .        .        .        .
 .       .       .       .       .       .       .       .       .
     .      .      .      .      .      .      .      .      .
   .     .     .     .     .     .     .     .     .     .     .
   .    .    .    .    .    .    .    .    .    .    .    .    .
 .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .
.  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .

Figure 3: A single image random text stereogram.

                      O              O
OIWEQPOISDFBKJFOIWEQPOISDFBKJFOIWEQPOISDFBKJFOIWEQPOISDFBKJF
EDGHOUIEROUIYWEVDGHOXUIEROIYWEVDGHEOXUIEOIYWEVDGHEOXUIEOIYWE
KJBSVDBOIWERTBAKJBSVEDBOIWRTBAKJBSOVEDBOWRTBAKJBSOVEDBOWRTBA
SFDHNWECTBYUVRGSFDHNYWECTBUVRGSFDHCNYWECBUVRGSFDHCNYWECBUVRG
HNOWFHLSFDGWVRGHNOWFGHLSFDWVRGHNOWSFGHLSDWVRGHNLOWSFGLSDWVRG
YPOWVXTNWFECHRGYPOWVEXTNWFCHRGYPOWNVEXTNFCHRGYPWOWNVETNFCHRG
SVYUWXRGTWVETUISVYUWVXRGTWVETUISVYUWVXRGWVETUISVYUWVXRGWVETU
WVERBYOIAWEYUIVWVERBEYOIAWEYUIVWVERBEYOIWEYUIVWLVERBEOIWEYUI
EUIOETOUINWEBYOEUIOEWTOUINWEBYOEUIOEWTOUNWEBYOETUIOEWOUNWEBY
WFVEWVETN9PUW4TWFVEWPVETN9UW4TWFVETWPVET9UW4TWFBVETWPET9UW4T
NOUWQERFECHIBYWNOUWQXERFECIBYWNOUWFQXERFCIBYWNOFUWFQXRFCIBYW
VEHWETUQECRFVE[VEHWERTUQECFVE[VEHWQERTUQCFVE[VEOHWQERUQCFVE[
UIWTUIRTWUYWQCRUIWTUYIRTWUWQCRUIWTXUYIRTUWQCRUIBWTXUYRTUWQCR
IYPOWOXNPWTHIECIYPOWTOXNPWHIECIYPONWTOXNWHIECIYLPONWTXNWHIEC
R9UHWVETPUNRQYBR9UHWVETPUNRQYBR9UHWVETPUNRQYBR9UHWVETPUNRQYB

Figure 4: A stereogram signature.

 IIIIIIIIIIIIIII   IIIIIIIIIIIIIII  
 H ( )  \|/    H   H   ( )   \|/ H  
 H(   ) -O-    H   H  (   )  -O- H  
 H     )/|\    H   H (     ) /|\ H  
 H======^======H   H======^======H  
 H- |----@-----H   H----| ---@---H  
 H /|\ @\|/ @  H   H   /|\@ \|/@ H 
 H    \|/  \|/ H   H     \|/  \|/H  
 III^IIIIIII^III   III^IIIIIII^III  
Wide eyed stereo  Wide  eyed  stereo

Moving animated versions of ASCII stereograms are possible too. ^{[citation needed]}