Magic Eye books were a huge fad in the mid-1990s — the kind of thing you’d find stacked on coffee tables, in bookstores, and even at mall kiosks.
They were filled with autostereograms, which are single, seemingly random patterns that hide a 3D image inside. To see the hidden picture, you’d have to use a special viewing technique: relax your eyes, focus as if you’re looking through the page, and let the image “pop” into view. Once you nailed it, a sailboat, dinosaur, or other scene would suddenly float in 3D right before your eyes.
Flashback Zach 