This excerpt from Walt Whitman's "To a Locomotive in Winter" uilizes another common poetic strategy at the beginning of each line, called __________________.

Question

Thy black cylindric body, golden brass and silvery steel.
Thy ponderous side-bars, parallel and connecting rod, gyrating, shuttling at thy sides.
 Thy metrical, now swelling paint and roar, now tapering in the distance,
Thy great protruding head-light fix'd in front.