A villanelle has a rather complex structure -- stated somewhat simply, it is a nineteen-line poem with two rhymes in its five stanzas and two lines that each are repeated (precisely or approximately) four times. These repetitions can lead to an interesting back-and-forth in the development of images and ideas. Although not about mathematics, this villanelle may, it seems to me, say a bit about mathematicians.
Running
Response (by JoAnne Growney) to “The Waking” by Theodore Roethke
My sleep is brief. I rise to run again,
to flee the doubts that catch me when I'm still.
I live by going faster than I can.