Aristotle explains that when a person stares at a moving stimulus such as the waves in a body of water, and then looks away, the next thing they look at appears to have a wavelike motion.
ˈæɹɪstˌɑːɾəl ɛksplˈeɪnz ðæt wɛn ɐ pˈɜːsən stˈɛɹz æɾə mˈuːvɪŋ stˈɪmjʊləs sˈʌtʃ ɐz ðə wˈeɪvz ɪn ɐ bˈɑːdi ʌv wˈɔːɾɚ, ænd ðˈɛn lˈʊks ɐwˈeɪ, ðə nˈɛkst θˈɪŋ ðeɪ lˈʊk æɾ ɐpˈɪɹz tə hæv ɐ wˈeɪvlaɪk mˈoʊʃən.