Which lines are parallel?
blue and red only
green and red only
green, blue and red
none
This is a well known Zöllner illusion, first described in 1860. It may be caused by this impression of depth. The black lines are parallel, too!
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Answers by country
blue and red only
green and red only
green, blue and red
none
answers

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319

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20072

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798

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