"Magic Eye" autostereograms were all the rage in the 1990s. You'd stare at the strange pattern, cross your eyes slightly, and a 3D image was meant to appear. Sometimes it worked for me, other times not. But in the moment when an image did emerge, I'd feel a strange meditative calm come over my mind and body, as if another universe had been revealed to me. Then I'd get a headache. In photographer/writer David Friedman's Ironic Sans newsletter, he reveals his undying appreciation for autostereograms beginning with a 1991 article in the great Omni magazine. Friedman introduces us to Scott Pakin, a computer scientist who creates fascinating and fantastic stereogram experiments. About the image above, Pakin writes:
Do you see pictures of faces or vases? (Look particularly at the top and bottom rows.) Here, I wanted to see if I could incorporate a Rubin vase—with my own shaggy profile— into an autostereogram. An SVG version of Faces and Vases is also available.
From Ironic Sans:
[Pakin] has around 75 of them, and they all stem from different ideas he wanted to try, like:
• Can you make a stereogram that includes lighting effects?
• Could you take a photo that's a stereogram?
• Could you make a stereogram that's also a valid QR code?
• What about a stereogram that's also an optical illusion?
Here's another fun one:

images: Scott Pakin (CC BY-NC-ND 4.0)