Here is the structure of the poem:
Stanza 1
Four lines, varying in length from 4 to 7 syllables
Stanza 2
Four lines, varying in length from 3 to 11 syllables
Stanza 3
Four lines, varying in length from 3 to 10 syllables
Stanza 4
Four lines, varying in length from 3 to 11 syllables
Stanza 5
Four lines, varying in length from 3 to 11 syllables
Stanza 6
Four lines, varying in length from 4 to 8 syllables
Stanza 7
Four lines, varying in length from 3 to 9 syllables
Stanza 8
Four lines, varying in length from 3 to 10 syllables
Stanza 9
Four lines, varying in length from 4 to 11 syllables
Stanza 10
Four lines, varying in length from 4 to 10 syllables
Stanza 11
Four lines, varying in length from 3 to 10 syllables
Stanza 12
Four lines, varying in length from 3 to 11 syllables
Stanza 13
Four lines, varying in length from 3 to 10 syllables