Black box sends a sign of fear and death because its unknown of whats in it. In the begenning of the story it talked about how the box has been a type of tradition for many years.
A form of imagery in the story was line 17 "smoothest and roundest stone." This form of imagery is being used to describe the types of stones that are chosen for the lottery. The description smooth and roundest stones are talking about the image of the stone.
This figure of speech used in the story is hominem where Tessie says "i tell you it wasn't fair". Tessie is saying this because she believes it isn't right about her family being picked.