Buzzfeed have compiled 10 wonderful animated illusions here. This is one of my favourites. When you look at the black dot the moving grey stripe will turn blue. Does it work for you? If not, look at the images of my books instead of at the black dot (thanks Julia!).



  1. yes it works for me.
    What I don’t understand is that I thought these sort of illusions normally worked by tiring out some of the receptor cells in the retina but this works instantaneously for me.

    1. ChrisR, this illusion works instantly because it’s how are brains are wired. The blue appears for 2 reasons: 1. because it is the opposite colour from orange, and 2. because as soon as we look away, the orange rectangle moves into our peripheral vision, where we can’t focus really well, which our brain rectifies based on previous experiences, so we keep thinking we see everything in focus. This is a survival skill, which turned out quite usefull. Unfortunately in this case, it’s also easily tricked, turning an indistuingishable grey bar into a more visible blue bar, increasing the contrast with the orange rectangle.

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