Symbolism in "The Lottery" by Shirley Jackson. What do the black box and stones represent?

Oppression, chance, death, archaic traditions.  Take your pick.  

The original paraphernalia for the lottery had been lost long ago, and the black box now resting on the stool had been put into use even before Old Man Warner, the oldest man in town, was born. Mr. Summers spoke frequently to the villagers about making a new box, but no one liked to upset even as much tradition as was represented by the black box.

The above lines of text indicate to the reader that the lottery process has been going on for a lot time.  The present box is not the original box, and the present box is looking incredibly worn.  That means it's old.  The box is only being used once per year, so it's not exactly a high use item that is getting worn out from frequent, overuse.  That means the lottery system has been in place for a very long time.  It's tradition.  It is suggested to Old Man Warner that the tradition might be so old that it is time to get rid of, but he simply scoffs at the idea. 

"They do say," Mr. Adams said to Old Man Warner, who stood next to him, "that over in the north village they're talking of giving up the lottery."

Old Man Warner snorted. "Pack of crazy fools."

Chips with people's names go into the box. Names are pulled out, and that person is stoned to death.  The box, the slips with names, and the stones are all tools of death and misery in the story.  Jackson never says why the lottery is in place, but it is a form of oppression and control.  Honestly, the concept is identical to The Hunger Games and its tributes.  That story also uses a lottery system to sentence people to die.