Villanelle is a form of
poetry. For an example see '
Do not go gentle into that good night'.
I have indicated the structure of a villanelle below. a,A1,A2 rhyme, as do all b's. A1 and A2 are the theme lines that are repeated throughout. / indicates a new line.
A1/b/A2
a/b/A1
a/b/A2
a/b/A1
a/b/A2
a/b/A1/A2