A big hello to all of the new people coming over to the blog!   Great to see you and I hope that you will also follow me on Twitter .

Today I am posting this a lovely and unusual illusion – simply stare at the dot and a moving gray bar will change into a strong green colour…..

How fascinating.  Anyone want to guess why it works?


  1. Ahh, the good old afterimage. There’s that other great one that has the pink circling dot that eventually disappears, I wish I knew a link to that. The effect is created by your eye wanting to see green after seeing pink. That’s how stop lights work, too, since the afterimage of red is green.

  2. I once had a similar effect by walking around with a video camera with a black and white monitor all day. When I stopped using the camera I could see a noticable difference in colour perception when I covered up each eye.

  3. I was going to say something about rods and cones and difference in perception depending on whether you’re looking direct or out of the corner of your eye…

    But it’s 3am and I’m too tired to find any info that’d back me up.

  4. You’ve disconcerted me with that evil laughing, wicked fellow! Why, as soon as I ‘get’ these things must I look away? I get all fidgety and something won’t let me bide any more time once the thing has changed. Brain no likey.

  5. As I type I have a green box fading on the corner of my vision on your grey background. Think I’ll stare at the sun for a bit to get rid of it…

  6. Afterimage! Our eye is afected by the magenta and we start seeing the opposite color, green. It has a physiological explanation, but I’m not a physiologist so…. hahaha.

    The evil laughter made me scare that an evil face was going to appear while staring at the dot. Bad joke people send through internet.

    Great blog btw!!! I just found it by mistake and I’m thrilled. Congrats!

  7. It’s more vague minty .. now, see if you can do that without the pink background …we can do nice colour tests .. with changing backgrounds.
    Not usefull? Aw ..

  8. did you do the trick with the 3rd eye/the demon inside of you ? Also nice when you date someone and don’t have a clue how to get upclose with that person (or what to talk about, or want to get a little more phsical)… sit close to eachother, facing eachother and stare eachother into the eyes … keep that up and observe eachother’s face …. the real person will emerge …

    On 2nd thought .. this might not be so good for dates …

  9. I’m color blind, and it works for me, too. I wouldn’t say “strong green”, but it definitely turns green, and there’s a distinctive green shadow when the box jumps from the left to the right.

  10. It works because the brain adapts after a while to ignore things. So the brain is trying to ignore the magenta background, which it does by making you percieve green, ever so slightly. The magenta fades from view. This lets you see the lion about to eat you, as opposed to the rock you’ve been staring at for an hour.

    However, the moving gray line can’t be ignored, so you get gray + subtracted magenta.

    Poof, green.

    == John ==

  11. Depends on the type of colour-blindness I suppose. Good illusion 😀 shame about the sound effects on the video though!

  12. I’m not colorblind at all and I followed the directions. For me, the bar remained gray. How is this possible?

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