I've often been fascinated by the asymmetry of Spanish meter. Lines of 11 accented on 4 break into two syllabic groups of 5 + 6.

"Mil Guadarramas / y mil soles vienen" (Antonio Machado)

Lines of 7 breaks into 3 + 4 or 4 +3.

"La sierra / gris y blanca" (AM).

The traditional combination of lines of 7 and 11 sylables, the silva, breaks into subgroups of 3s, 4s, 5s, 6s. It's a marvelous thing. A hendacasyllable with accent on 6 tends to break up into 7 + 4, the counterpoint to the 5+6. This knowledge is almost secret.

Of course they'll tell you the 11th syllable is extra=metrical. It is, for counting purposes, but I think these extra syllables have a rhythmic function. Imagine if 90 per cent of English iambics had "feminine" endings? Wouldn't that change a lot?

If someone could fully integrate linguistic prosody with poetic prosody they would win the Nobel prize or something.