If 16 scanlines of continuous graphical data are written to a character-block-aligned portion of the screen then they will appear as a continuous block in most modes but in the two non-continuous modes they will be displayed as two blocks of 8 scanlines, separated in the middle by two blank scanlines.
ɪf sˈɪkstiːn skˈænlaɪnz ʌv kəntˈɪnjuːəs ɡɹˈæfɪkəl dˈeɪɾə ɑːɹ ɹˈɪʔn̩ tʊ ɐ kˈæɹɪktɚblˈɑːkɐlˈaɪnd pˈoːɹʃən ʌvðə skɹˈiːn ðˈɛn ðeɪ wɪl ɐpˈɪɹ æz ɐ kəntˈɪnjuːəs blˈɑːk ɪn mˈoʊst mˈoʊdz bˌʌt ɪnðə tˈuː nˈɑːŋkəntˈɪnjuːəs mˈoʊdz ðeɪ wɪl biː dɪsplˈeɪd æz tˈuː blˈɑːks ʌv ˈeɪt skˈænlaɪnz, sˈɛpɚɹˌeɪɾᵻd ɪnðə mˈɪdəl baɪ tˈuː blˈæŋk skˈænlaɪnz.