CSS Optical Illusions(alvaromontoro.com)
152 pointsby ulrischa11 hours ago9 comments
  • myfonj8 hours ago
    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)

  • brandon_bot3 hours ago
    Cool!

    I did something similar for my personal favorite illusion, the Ames window illusion. Recreated with CSS: https://brandondong.github.io/blog/ames_window/

  • sandpaper2610 hours ago
    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.

  • nilslindemann10 hours ago
    33 - color fan: There is another interesting optical illusion here: The fan seems to rotate faster when not directly looking at it.
  • layer85 hours ago
    Heh, I used to do these in Excel.
  • eulgro4 hours ago
    They could make capchas out of these.
  • encom10 hours ago
    These are all super dark, for some reason.
    • christophilus9 hours ago
      You have to actually run them. Otherwise, they're just a dark CodePen preview.
      • encom9 hours ago
        Why the extra step of having to click each one? Only a few of them are interactive.
        • d-us-vb8 hours ago
          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.

          • zamadatix8 hours ago
            Somewhat ironically, Codepen ended up introducing the JS execution requirement to view the content.
  • moralestapia10 hours ago
    Wow, this is great!

    I want to put some of them in my UIs.

    • herpdyderp7 hours ago
      I've often run into these unintentionally messing up my UIs!
  • 8 hours ago
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