A
Story
CSS Optical Illusions
These "dots appearing only while (not) focused" are known as "extinction illusions", namely

    "25 - Appearing Dots"
is "McAnany's type" [1], and

    "26 - Disappearing Dots"
is known as "Ninio's type" [2], according Akiyoshi Kitaoka's materials. (I have recreated them too few years ago [3][4], before getting to the source.)

[1] https://www.psy.ritsumei.ac.jp/akitaoka/kieru3e.html#:~:text...

[2] https://www.psy.ritsumei.ac.jp/akitaoka/kieru3e.html#:~:text...

[3] https://codepen.io/myf/full/XjdmJy ( scintillation warning)

[4] https://codepen.io/myf/full/jMqoMW ( scintillation warning)

This is cool, but more as a demonstration of interesting CSS techniques than optical illusions in my opinion.

Also, interestingly, I seem to be able to force myself to "see through" all of these illusions except for induced gradients, which I can't stop seeing unless I cover part of the screen.

  • eulgro
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  • 27 minutes ago
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They could make capchas out of these.
33 - color fan: There is another interesting optical illusion here: The fan seems to rotate faster when not directly looking at it.
Heh, I used to do these in Excel.
  • encom
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  • 5 hours ago
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These are all super dark, for some reason.
You have to actually run them. Otherwise, they're just a dark CodePen preview.
  • encom
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  • 4 hours ago
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Why the extra step of having to click each one? Only a few of them are interactive.
Because codepens can run javascript. And if a page has 50 of them, it might make the page load time much longer. I know that all these examples are pure CSS, and maybe there is a setting in codepen to disable the "Run" button and automatically run it. Still, getting to decide is generally a better pattern than presuming that that's what the user wants, especially when the fact that the code is inside a codepen makes it explicitly not an integral function of the page. "I thought this was just a blog, and now you want me to run all this javascript??" -- some JS hater, probably.

I appreciate getting to choose as much as possible when code runs.

Somewhat ironically, Codepen ended up introducing the JS execution requirement to view the content.
Wow, this is great!

I want to put some of them in my UIs.

I've often run into these unintentionally messing up my UIs!
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  • 4 hours ago
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