rhetorical devices - What figure of speech is this?

"Cannon to the right of them,

Cannon to the left of them,

Cannon in front of them."

Years ago, when I was introduced to "The Charge of the Light Brigade" (Tennyson, 1854) our teacher pointed out the repeated use of the word "cannon", like a refrain, was a figure of speech. He went on to give other examples, of which my mind retained only this:

Victory at all costs,

victory in spite of all terror,

victory however long and hard the road may be. (Winston Churchill, June 1940)