- Scientists still don't understand exactly how some optical illusions play tricks on people's eyes.
- Johann Karl Friedrich Zöllner, a German astrophysicist, discovered the Zöllner effect, which caused parallel lines to be curved in 1860.
- One of the first ambiguous images (images showing two things at once) was published in a German magazine in 1892.
- The McCollough effect makes black and white stripes colored, discovered by Celeste McCollough in 1965.
- Visit the INSIDER's more story site.
Optical illusions often go viral on social media, but they have been around long before Twitter.
From straight lines looking oblique to ambiguous images that can be interpreted in a number of ways, these illusions have encountered scientists and lies for decades (and in some cases centuries).
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