The runback is the most rare of the conversion rules, and is most often implemented in one-on-one games.
ðə ɹˈʌnbæk ɪz ðə mˈoʊst ɹˈɛɹ ʌvðə kənvˈɜːʒən ɹˈuːlz, ænd ɪz mˈoʊst ˈɔfən ˈɪmplɪməntᵻd ɪn wˈʌnˌɔnwˈʌn ɡˈeɪmz.