A terzanelle is a 19-line poem of five triplets (3-line stanza) and a concluding quatrain (4-line stanza).  It incorporates aspects both of a terza rima and a villanelle; the middle line of each triplet is repeated verbatim as the third line of the following stanza, but the first and third line of the initial stanza also become the second and fourth lines of the closing quatrain. Thus seven of the 19 lines are actually repeated in this form.  

The rhyme scheme of the six stanzas is a follows, with the Capital letters indicating the lines that are completely duplicated:

A¹BA²
bCB
cDC
dED
eFE
fA¹FA²

An alternate ending for the final stanza is:

fFA¹A²