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Optical illusion

  1. Dec 26, 2004 #1
    This optical illusion is driving me nuts. I know the answer. I know the two squares are the same color, but I cannot convince my brain to believe it.
    there are a few neat optical illusions here http://web.mit.edu/persci/gaz/#
    Last edited by a moderator: Apr 21, 2017
  2. jcsd
  3. Dec 26, 2004 #2
    This is cooler. Print out that picture. Then cut down in such a way that you slice squares A and B into the same shape. Then move half of A beside hald of B.
    It's amazing, they'll both look different but once you blint they'll both look the same shade.
  4. Dec 27, 2004 #3

    Ivan Seeking

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    Me either. I can usually see these things but that one eludes me. I had to print it out to convince myself this wasn't bogus. At first I didn't believe it!
  5. Dec 27, 2004 #4
    Check this one out: The two centers are the same shade of grey.

    http://pics.bbzzdd.com/users/moomoo40moo/opt1.jpg [Broken]
    Last edited by a moderator: May 1, 2017
  6. Dec 27, 2004 #5

    Your pic doesn't work. Upload it to www.imageshack.us and then try again.
    Last edited by a moderator: May 1, 2017
  7. Dec 27, 2004 #6
  8. Dec 27, 2004 #7
    my mouse pointer is a white arrow. when I drag it over the blue square the arrow turns yellow
  9. Dec 27, 2004 #8


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    I cannot believe that. They are not equally shaded!!.It is impossible!! :confused:
    Last edited by a moderator: Apr 21, 2017
  10. Dec 27, 2004 #9
    Your cursor turns yellow? My cursor doesnt appear to change, maybe your cursors magic.
  11. Dec 27, 2004 #10
    or check out this one
  12. Dec 27, 2004 #11
    No they aren't..
  13. Dec 27, 2004 #12


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    I don't see the same color anywhere.

    See this:


    she is a naked girl, can you see her? (kidding) :rofl:

    I mean, I don't see the same color. Do you see it really?
  14. Dec 27, 2004 #13
    lol, I was curious to see if anyone took these optical illusions for granted. So I drew one that was obviously untrue to see if anyone would just accept it.
  15. Dec 27, 2004 #14
    How about this: :bugeye: :bugeye: :bugeye: :bugeye: :bugeye:
    http://www-inst.eecs.berkeley.edu/~mlow/sosmath/effect.jpg [Broken]
    Last edited by a moderator: May 1, 2017
  16. Dec 28, 2004 #15
    Here are two.

    The Bob (2004 ©)

    Attached Files:

  17. Dec 28, 2004 #16
    Well, neither do I. But this pic shows it all:

    http://www.grand-illusions.com/images/shades%20illusion2.jpg [Broken]

    By the way I really like the optic illusion found be Omicron. :bugeye:

    http://www.michaelbach.de/ot/fcs_hollow-face/icon.gif [Broken]
    Sorry for the size.
    Last edited by a moderator: May 1, 2017
  18. Dec 29, 2004 #17
    More impossible rotations
  19. Dec 29, 2004 #18
  20. Dec 29, 2004 #19
    The slope of the triangle is different. In one of the triangles is not a line
  21. Dec 29, 2004 #20


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    Neither of the "triangles" is really a triangle. They both supposedly have a slope of 5/13 (=0.385), but since 5 and 13 are relatively prime, you can not recreate this slope with smaller integers. This tells you that the slopes on the red and blue triangles must be different from that of the overall "triangle". A quick check confirms this.

    The red triangle has a slope of 3/8(=0.375) and the blue one has a slope of 2/5 (=0.4). Since one of these slopes is bigger, and the other smaller, than that of the overall "triangle", their arrangement determines the concavity or convexity of the overall shape. In this case, the uppex figure is slightly concave while the lower figure is convex on the slopy side.

    The difference in areas between these slivers accounts for the missing square.
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