Illusions

We believe in what we see. Still there are some conditions in which human eyes can be fooled. This is called illusions.
Here are some examples of Illusion.

Is this moving?

How many grey dots are there in the above picture?

Mark left and right legs of the elephant.

Are the buds in the above picture moving or still?

Can you believe that square 'A' and square 'B' are of same darkness?

Are the horizontal lines in the above picture parallel to each other?

Which circle is bigger? Black one,or white one?

A brain teaser.