Takes me back to organic chemistry classes decades ago where molecules were often printed in stereo pairs to break out of 2D thinking about 3D structures. One could use special glasses or train the eyes to see them. The latter method had the risk of getting left/right reversed which is a big deal when looking at chiral molecules where "handedness" is critical.
Scientific papers use (still?) stereo images, for example those made using ORTEP:
although seeing something like an alfa-helix as 3D might require some familiarity with the structure in the first place!
Thanks for the pointer! I haven't followed the chemistry/biochemistry literature for years. I just assumed that 3D visualizations would have taken over.
I have had a burning question about these since forever. Why do e.g. the Magic Eye books use divergent, not convergent (i.e. crossed-eyes) types? I find it much easier to control position and focal length when crossing my eyes. I wonder about others' experiences.
That's my experience. I have to trick my eyes to see it in 'divergent' mode. But all I have to do is cross my eyes and I can see the image. Although, I would see shapes sinking into the page not popping out.
Divergent mode is much easier for me. I just unfocus my eyes (the same muscle that blurs them).
I can easily diverge, but I then can't control focus. Do you see the stereograms in focus?
This can be practiced! I was super into stereograms years back and have decent control now (not intentionally but happened naturally). Can slightly diverge to see smaller/far-away images or maximally diverge for the bigger/close-up images.
I had never heard of SIRDS before. That's a very cool way to potentially show stereograms to folks that struggle to see them!
Seems like this wiki page has some of the same example images: