In Which Direction Do They Spin?

Michael caught a remarkable show on National Geographic the other day, featuring some of the most interesting optical illusions of our time. Most of them we have already featured on this site. One of the featured illusions that made him scratch his head were the spinning balls you can see in this animation below. This is how it works: both of the outer rims (made from spinning balls) rotate in counter-clockwise direction. But if you try and focus on one of the central dots (i.e. yellow one), the outer rim of another will seem to spin in opposite direction! This works vice-versa. To put it short – concentrating on the yellow ball will make it seem that the balls on the left are turning in opposite direction, while in fact they aren’t! Strange isn’t it?

Can you tell in which direction do the balls spin?
Can you tell in which direction do the balls spin?

23 Replies to “In Which Direction Do They Spin?”

  1. Hmm. I am not seeing this one. They both look like they are going counter-clockwise no matter which dot I focus on.

  2. Try to focus on the message “Can you tell in which direction do the balls spin?”
    All those balls go clockwise! :D

    1. You’re right, it works! Is this like what happens in cars, when the wheels look like they are turning slowly the other way?

    2. Wheel reversal happens because as the wheels spin quickly, your eyes can only pick them up at a limited rate, sometimes the “frames” your eyes pick up make the image appear to go in the other direction.

      This is similar in that your peripheral vision picks up motion differently than your direct vision.

  3. Wow! amazing illusion. Even if you focus on the right area, you can even suspend the other clock!

  4. If you look above and middle they both spin counter-clockwise.

    If you look below and middle they both spin clockwise.

    Very nice effect.

  5. Another neat trick is to bring the red and yellow dots together (almost 3D-like). Then try to alternate the red and yellow dot on top of the other.

  6. awesome – i love it
    both clearly clockwise when you stare at them – but notice the one you aren’t looking at changes direction

  7. you you look above or below the circles, you get the strongest illusion of clockwise motion. I noticed this while reading the paragraph above and the caption below
    also looking the the left and right.
    Appears to have something to do with peripheral vision.

  8. I couldn’t see it for ages, then I could-they do move in different directions if you look at them in just the right way…

  9. It’s going to the left, the lines are confusing your mind into thinking they are going opposite ways.

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