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> Yup. Those aren’t spirals. They’re all concentric circles. Except they are spirals. The black patches form the implication of a spiral - this is where your

by vacri 9y ago

> Yup. Those aren’t spirals. They’re all concentric circles. Except they are spirals. The black patches form the implication of a spiral - this is where your visual system picks out the spiral from. If you were to say that there are technically no spirals in that image because they're not contiguous, then you could equally say that there are technically no circles either, only an arrangement of square boxes that is strongly suggestive of a circle. Either way, it's a very powerful illusion.

qbrass 9y ago
>If you were to say that there are technically no spirals in that image because they're not contiguous, then you could equally say that there are technically no circles either, only an arrangement of square boxes that is strongly suggestive of a circle. There are circles though. The grey concentric rings. If you removed them, you'd see the black and white pattern spirals towards the center.
- deleted 9y ago
  [deleted]
ghusbands 9y ago
This is something I've been tempted to blog about. As you and my sibling poster point out, the illusion is actually essentially composed of the things they claim aren't there. The same goes for the Kanizsa triangle, Fraser's illusion and many others. The simplest description of each image matches what our eyes see, but the creators say "Ah, but I created it this other way, so your eyes are wrong".
- dwringer 9y ago
  For me the illusion here is no trick. Looking at it I have considerable difficulty not seeing a single unbroken line spiraling out from the center to the perimeter. In reality there are huge disconnects, it is concentric rings and not a continuous line at all. Even when I force myself to see the circles they look like they are all trying to float away from each other in opposite directions. Almost poetic, really.
  - ghusbands 9y ago
    The spirals are actually there, partially concealed by plain circles, so seeing spirals is not really incorrect. Your visual system is good at seeing concealed things. That's why I disagree with it being classified as an illusion. Though not as much as with the Kanizsa triangle.
    - dwringer 9y ago
      "The spirals are actually there" - the unbroken spiral is not there, and it is an illusion of one, not multiple. At least to me. I guess if you want to be particular, the circles are broken by the pixels on my monitor, but at 4k that isn't perceptible. I guess if one gets far enough away from the monitor that one can no longer resolve the space between the circles it could be said that the spiral is actually there.
userbinator 9y ago
The black patches form the implication of a spiral Indeed, it reminded me of the triangle illusion: https://en.wikipedia.org/wiki/Illusory_contours https://en.wikipedia.org/wiki/Illusory_contours The brain is very good at "filling in", so what it's doing in this case is perceiving the image as a masked-off spiral. That also brings to mind, what would the "content-aware fill" tool in newer versions of Photoshop do to the image...?

by vacri 9y ago

qbrass 9y ago

>If you were to say that there are technically no spirals in that image because they're not contiguous, then you could equally say that there are technically no circles either, only an arrangement of square boxes that is strongly suggestive of a circle. There are circles though. The grey concentric rings. If you removed them, you'd see the black and white pattern spirals towards the center.

deleted 9y ago
[deleted]

ghusbands 9y ago

This is something I've been tempted to blog about. As you and my sibling poster point out, the illusion is actually essentially composed of the things they claim aren't there. The same goes for the Kanizsa triangle, Fraser's illusion and many others. The simplest description of each image matches what our eyes see, but the creators say "Ah, but I created it this other way, so your eyes are wrong".

dwringer 9y ago
For me the illusion here is no trick. Looking at it I have considerable difficulty not seeing a single unbroken line spiraling out from the center to the perimeter. In reality there are huge disconnects, it is concentric rings and not a continuous line at all. Even when I force myself to see the circles they look like they are all trying to float away from each other in opposite directions. Almost poetic, really.
- ghusbands 9y ago
  The spirals are actually there, partially concealed by plain circles, so seeing spirals is not really incorrect. Your visual system is good at seeing concealed things. That's why I disagree with it being classified as an illusion. Though not as much as with the Kanizsa triangle.
  - dwringer 9y ago
    "The spirals are actually there" - the unbroken spiral is not there, and it is an illusion of one, not multiple. At least to me. I guess if you want to be particular, the circles are broken by the pixels on my monitor, but at 4k that isn't perceptible. I guess if one gets far enough away from the monitor that one can no longer resolve the space between the circles it could be said that the spiral is actually there.

userbinator 9y ago

The black patches form the implication of a spiral Indeed, it reminded me of the triangle illusion: https://en.wikipedia.org/wiki/Illusory_contours https://en.wikipedia.org/wiki/Illusory_contours The brain is very good at "filling in", so what it's doing in this case is perceiving the image as a masked-off spiral. That also brings to mind, what would the "content-aware fill" tool in newer versions of Photoshop do to the image...?