The paper symbolizes the random choosing of someone's death. It symbolizes this because of the fact that everyone in the town has to pick a piece of paper. If they don't someone else has to pick for you. You have a small chance of getting the black dot, but its still possible.
Tone - Suspense
"Who's gonna win?"
"I have no idea but I'm really nervous..."
"The flowers wre blossoming profusely and the grass was richly green." The image shows many flowers with dark green grass. This can also be used as symbolism in a "Life before Death" way.
Images - Stones
"People ain't the way they used to be." is slang because of how the speaker said "ain't" instead of "are not", shortening the phrase.
No one knows who's going to win the lottery, so it leaves them in suspense. A lot of people truly don't want to participate in the lottery. However, since its tradition, no one has dropped it. They don't want anyone to die but they must.
"There were stones in a pile." The stones can also be used as symbolism along with the flowers in the grass field. They show "Duality of man" since they are used to kill whomever has the black dot paper. The kids helped put rocks in a pile so everyone would be ready to stone their fellow neighbor.