Which technique is the author using in this stanza?

ten thousand eyes were on him as he rubbed his hands with dirt;
five thousand tongues applauded when he wiped them on his shirt.
then while the writhing pitcher ground the ball into his hip,
defiance gleamed in casey’s eye, a sneer curled casey’s lip.

simile
alliteration
imagery
onomatopoeia

blank verse is often confused with free verse. free verse avoids traditional poetic forms such as rhyme schemes and conventional metres and can follow any pattern the poet wishes which means that the verses and lines can differ in length as the poet chooses. however blank verse like free verse is also unrhymed but each line in blank verse has roughly the same number of stresses and syllables, usually following the iambic pentameter