You can view it here on the hidden-3d.com site.
If you stare at the text and let your focus land some distance behind the screen, you should see something... interesting.
Anyway. I'm telling you about this because I just received email from a very nice person who wanted to know more about it for a class they are teaching, and I have nearly finished an email back to them giving the Whole Secret Away.
Since I'm doing that anyway, I thought I'd post it here too.
So, herewith: instructions for writing stereoscopic poems:
I figured it out when I was trying to make regular steroscopic images myself, and was researching online. Turns out the trick is to have multiple identical columns of... stuff... can be anything really... hence the sort of colourful white noise that most of the pictorial stereoscopic images use - what you do is you place several of those columns next to one another and then change ever so slightly just the parts that you want to 'pop' from the image, but only in some of the columns, not all of them.
This becomes particularly clear if you look at the other abstract ASCII stereograms on the http://www.hidden-3d.com/ site.
Don't ask me why. I'm a writer (and sometime coder), not a physicist, neuroscientist or opthamologist :)
Anyway. So the trick to writing one of these is this:
- Write a long poem. About anything. Doesn't matter. Short lines are essential for this though, so you'll need to bear that in mind.
- The hard bit. Make a shorter poem a) using only words that occurred in the longer poem, and b) in the *exact* order they occurred in that poem. You can only use each word once. It's as if you are skipping through the longer poem, missing out all the words except for the ones that make up your new poem.
- Type your long poem out in a column, then duplicate it three times. ESSENTIAL - use a fixed width font like Courier. I found that drawing columns using '*' helped but this is not necessary. Haven't done this in seven years but I seem to remember that it *had* to be four columns - three didn't work and nor did five. Can't remember why and I may be wrong.
- In each column of the long poem, add an extra space on one side of each of the words from the shorter poem.
- For each word of the shorter poem, choose a column where you want it to pop out and flip the side of the word where the space occurs, in that column *only*.
- That's it.
I found that columns of about 25 characters in width were ideal, but YMMV.
If you write one, let me know. I'd love to read it.