Let seed be grass, and grass turn into hay:
 I’m martyr to a motion not my own;
 What’s freedom for? To know eternity.
 I swear she cast a shadow white as stone.
 But who would count eternity in days?
 These old bones live to learn her wanton ways:
 (I measure time by how a body sways).
 Source: Roethke, Theodore. “I Knew a Woman.” The Collected Poems of Theodore Roethke. New York: Random House Inc., 1961. Poetry Foundation. Web. 9 June 2011.
  
 Which excerpt is a simile that indicates a thoughtful mood?