leda 1, leda 2, leda 3 by Lucille Clifton   Some years ago, while teaching a graduate poetry workshop at the University of Memphis, I was describing the volta to the students as rhetorical and structural turning points we can identify in many poems, not only in sonnets.  I was suggesting that, more broadly defined, the volta consists of instances where a poem swiftly shifts gears and careens around a curve, creating surprise…when one of the students interrupted to admit that as I had been saying “volta,” over and over, she had been hearing “vulva” each time.  This was a class of all women and we had been having a raucous time in some of the previous class sessions.  For the rest of that…