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Optical illusion

Herman grid

How many black dots can you count?

The Herman Grid is a black rectangle, broken into smaller black squares – 8 across and 6 from top to bottom – by grey lines. At each intersection there is a round white dot. It is inside each of these white dots that the eye is aware that there appear to be slightly smaller black dots. But as the eye looks at each black dot in turn, it disappears and only the white dot can be seen while, at the same time, being aware that there are black dots in the other intersection white dots that one is not looking at. Therefore, it is impossible to focus on any of the black dots – if you look directly at them, they disappear.

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Answer

Did you know?

Eating brocoli, spinach and other similar vegetables regularly can help prevent eye disease. Find out more