ðeɪ ɑːɹ jˈuːzd fɔːɹ spˈɛʃəl pˈɜːpəsᵻz, mˈoʊst ˈɔfən ɪn kəmpjˈuːɾɚ ɡɹˈæfɪks, wˌɛɹ ˌɪɾɚɹˈeɪʃənz ɑːɹ smˈɔːl ænd pɹɪsˈɪʒən hɐz ɛsθˈɛɾɪk ɪfˈɛkts.
They are used for special purposes, most often in computer graphics, where iterations are small and precision has aesthetic effects.