Here we go, like in the first picture below. In the picture, there are two groups of dots are displayed. The right group seems to have a bigger dot at the centre. Nope you are wrong, both central dots have the same diameter! This pic is playing tricks on your eyes!
Here in the second picture, all you have to do is to keep staring at the black dot at the centre. After a while you will see that the grey haze that surrounds the dot will start to shrink until it almost completely disappears. That's because as you focus on the central dot, your brain starts to ignore the surrounding objects! But as your focus is away from the dot, the shade begins to reappear!
In the picture below, you see yellowish green arrows on the blue background. All you have to do is to stare at them for a few seconds. You will see as if the arrows are moving very slowly.
Illusions like those above are everywhere to be found on the web. You can find them easily. I would just like to show you those illusions could be very fun and enjoyable. Feel free to look for more of them!
(Written by: Yari NK. Pictures taken from the Web)