Jastrow Illusion

Which of these dildos is longer? The blue one appears to be longer, but they are exactly the same size

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How it works: The Jastrow illusion is named after psychologist Joseph Jastrow, who demonstrated it in 1889 using two identical curved shapes. The placement of the dildos is such that when you look at them you are comparing the inside, shorter curve of the red dildo to the longer outer curve of the blue dildo. In addition, you don’t really notice that the blue dildo is placed further to the right because of the way the dildo bases are lined up on the left.