Windbags can be right. Aphorists can be wrong. It is a tough world. - James Fenton

It is not what they built. It is what they knocked down.
It is not the houses. It is the spaces between the houses.
It is not the streets that exist. It is the streets that no longer exist.

Tennyson follows his feelings in creating each line. He follows the music in his head. If you had asked him, at the end of the day, to describe the prosody of the poem to you, he would no doubt have had to think for a moment before he could answer you, not because he was ignorant of the terms, but because he had been writing a poem, not a metrical exercise. At every point, he was exerting his free will. And the outcome of that exertion was the form.

Among those today who believe that modern poetry must do without rhyme or metre, there is an assumption that the alternative to free verse is a crash course in villanelles, sestinas and other such fixed forms. But most...are rare in English poetry. Few poets have written a villanelle worth reading, or indeed regret not having done so.