c. The contiguous vowels may come after the accented syllable.
a. Two contiguous vowels before the accent.
(1) Of the twenty-five possible combinations all are admissible in diphthongs in a syllable preceding the accented syllable.
Ex. Habrá po^esta, p. 165, IV, l. 4.
(a) Diaeresis may be employed to dissolve the diphthong.
Ex. Sobre una vi|oleta, p. 169, XIII, l. 8.
b. One of two contiguous vowels accented.
(1) When two contiguous vowel's are strong.
(a) There is no diphthong if one of two contiguous strong vowels receives the accent.