The Müller-Lyer illusion is an optical illusion where two lines of the same length are perceived to have different lengths, due to one line having arrow-heads at its ends and the other having arrow-tails.
The Müller-Lyer illusion is an optical illusion where two lines of the same length are perceived to have different lengths, due to one line having arrow-heads at its ends and the other having arrow-tails.