Breathing Square Optical Illusion

This one actually is really good (as simple as it may appear)! Observe the animation on your right: behind a grid of yellow boxes there is a purple rotating square. As the square rotates, we only see the part of it not covered by the grid. It appears to grow and shrink in its roatation, as if it were breathing! Am I right?

In reality none if this is true – the square remains same in size at all times. It’s just that our brain perceives it “breathing” and changing size. Would be cool if someone could make a solution .gif file, without the yellow grid and attach it through comments… anyone? Hope you like these simple, old-school illusions the same way you like real-life ones?

32 Replies to “Breathing Square Optical Illusion”

  1. I became curious and redone both the original and the explanation. It’s a little rough with a smaller number of frames.
    [img]http://amsoft.ru/tmp/rotating-square-anim1.gif[/img]
    [img]http://amsoft.ru/tmp/rotating-square-anim2.gif[/img]

  2. Well, are you sure it’s an illusion?… even if the square’s size remains the same, the size of its visible surface really change. So it shrink of course…

    1. That html5 example just shows what a mess the html5 “standard” is. You have to have 5 separate blocks of code; the “standard”, one for IE, one for Opera, one for Safari/Chrome and one for Firefox.

  3. [img]http://img.photobucket.com/albums/v287/akuma-hime/Solution.gif[/img]

    It’s a simple but effective illusion. Since you asked for a solution gif, I went ahead and made a really quick one. Hope this helps show that the blue square is just rotating and not changing size! ^_^

  4. well this is something i’ve never seen before, incidently, do you have any of those illusions where you drag a striped piece of paper over an image and make it look like it’s animated?

  5. I actually doubted that the effect was real, and so decided to check if it was a trick. I took an image using the Print Screen function when the corners of the square were in the cross, pasted the image into paint, measured the hypotenuse of the square with a real ruler on my screen, and calculated what the side length would be. I then took a second image when the sides of the square were vertical, and measured the length from one side to the other. Boy do I feel stupid; the square isn’t changing size after all. I also would like to apologize for doubting you Vurdlak. Sorry that I did not trust your judgement.

  6. Wow.

    I stared at it a while before reading the post and couldn’t see any illusion. Then I read your post and was absolutely floored by what the illusion was.

    A really powerful illusion.

    1. Tom and John, I didn’t notice the split second circular look until I read your posts but I do see it.
      Cool illusion!

  7. Did you notice that when the blue square is not moving (and is in the same horizontal plane as the other 4 squares) sometimes when you are looking at one of the brown squares the blue square can appear to be a circular.

  8. What is all the fascination and wonderment with is? If you were viewing the silhouette image of May West through only a very narrow horizontal slit opening in a piece of paper and moving it up and down, would you be saying that what you can see though the slit is a magical illusion? Hmmm. Hey, I take this all back. Substitute whomever voluptuous bombshell you can think of and analyze this to death. Looking forward with whatever the greatest minds can conjure up. I love science.

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