Subject: Random dot Stereogram -> torus.ps

From: [email-masked] (Andy Kinsman 253-7794)
Date: 12 Jun 92 15:58:11 GMT

I hope this keeps you random dot stereogram people happy.
It plots a torus on postscript printer, in landscape mode.

to view on a sun box at least...

  1. cut out the file below
  2. uudecode file               -> yields torus.ps.Z
  3. uncompress torus.ps.Z       -> yields torus.ps
  4. ship it to a printer...     -> try "lpr torus.ps"

If you show it to a group of people, and more than 15%
can see it, tell me how you displayed it so that they could.

I have about twenty others, including fractals.  Now the
focus is on scanning really interesting subjects:-) But I
don't know what groups to post those to.  The first 4-5
off the press were shipped to the Stereo World magazine.

Look for my name in the bottom border. -AAK

[email-masked]

CUT-HERE-CUT-HERE-CUT-HERE-CUT-HERE

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From: [email-masked] (Tom Schneider)
Date: 18 Jun 92 21:18:55 GMT

In article <[email-masked]> [email-masked]
(Hien Huu Nguyen) writes:
|In article <[email-masked]>, [email-masked]
| (David Knapp) writes:
|> In article <[email-masked]> [email-masked]
|> (Andy Kinsman 253-7794) writes:
|> >I hope this keeps you random dot stereogram people happy.
|> >It plots a torus on postscript printer, in landscape mode.
|> 
|> *Please* post more of these! These are TOO COOL!
|> 
|> Can you expound on the process used to create these?  This was really quite
|> striking.
|> 
|How about expounding on the process to SEE these?  Try as I might, I couln't
|see anything. What am I missing?
|Hien Nguyen [email-masked] (also try [email-masked])

Unfortunately these, although beautiful, are not good to learn the method
with.  I suggest pulling out a few issures of the Journal of Molecular Biology
where there are often good stick figure sterio pictures of molecules.  The
sterio pairs are usually presented on the page so that the left one should be
seen by your left eye and the right one should be seen by your right eye.
Don't cross your eyes.  When you look at something in the far distance your
eyes are like this: || (parallel).  When you look at something close, they will
be like this:  /\ (focused to a point).  The idea is to have the eyes parallel
so that each sees the right image, but in focus on the page.  Start by looking
at something far away.  On David Knapp's image there are two triangles.  If you
have the paper near your eyes as you look far away, there will probably be 4
triangle images, and they will be fuzzy.  The trick will be to get what looks
like 3 triangles.  The middle one is the fused image.  You are to ignore the
outer two.  Ok, here's what to do.  Put those triangles on the top of the page,
and put the page just under your line of sight.  Look to the far distance.
RELAX!  Allow your eyes to drift down onto the page where the triangles are,
but don't focus.  Allow the triangles to overlap.  You may have to rotate the
page a little to get them to overlap (they have to line up with your eyes,
right?)  Concentrate on getting them to overlap, and don't worry that they are
fuzzy.  Once they overlap, slowly allow them to come into focus.  As you
succeed in doing this the torus will begin to appear further down on the page.
You can carefully move your eyes down and explore it.  The center is pretty
neat.  You can see the layers on it also.

It is really better to do this while the page is lying flat and still, since
the stereo effect will be destroyed if you move too much relative to the
paper.  Also, before you start, make sure that the lighting is the same on both
stereo parts (or across the image in the case of the random dot ones), to avoid
distracting highlights.

Don't worry.  It takes some practice to do it, but the images can be
spectacular.  Often they feel more three dimensional than real objects!

  Tom Schneider
  National Cancer Institute
  Laboratory of Mathematical Biology
  Frederick, Maryland  21702-1201
  [email-masked]

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From: [email-masked] (David Watson)
Date: 19 Jun 92 01:12:12 GMT

[email-masked] (Tom Schneider) writes:

>I suggest pulling out a few issures of the Journal of Molecular Biology

See the article

Speakman, J.C., 1978, Visualising molecules without really trying your eyes,
New Scientist, vol. 78, p. 827.

--
Dave Watson                           Internet: [email-masked]
Department of Mathematics            
The University of Western Australia               Tel: (61 9) 380 3359
Nedlands, WA 6009  Australia.                     FAX: (61 9) 380 1028

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From: [email-masked] (Adam Mirowski)
Date: 19 Jun 92 13:48:41 GMT

In article <[email-masked]>, [email-masked] (Russ Nelson) writes:
%% In article <[email-masked]> [email-masked] (Andy Kinsman 253-7794) writes:
%% 
%%    I hope this keeps you random dot stereogram people happy.
%%    It plots a torus on postscript printer, in landscape mode.
%% 
%% Hey!  That's not a torus!  That's a stacked pile of flattened cylanders,
%% each with a smaller ID and OD than the one below it.  Look carefully
%% and you'll see what I mean...

More seriously, I can see 2 images on this picture: either a big torus
or a 2-hole smaller torus on the top of a hill (:-)).
In the first case, I see 3 triangles on the top of the figure.
In the second case, I see 4 equally spaced triangles, so my eyes
are probably even more diverging.

-- 
Adam Mirowski,  [email-masked] (FRANCE),  tel. +33 (1) 30-64-82-00 or 74
Chorus systemes, 6, av.Gustave Eiffel, 78182 Saint-Quentin-en-Yvelines CEDEX