Ms Perovski was writing on the board. She didn't see us lean the chairs against the back wall again. She'd told us to stop leaning back on them. They aren't stable supported on only two legs, she kept telling us. When she turned back to the board, I told everyone to do it again as a joke.

I did it first. I jerked up my chair and then the others followed. I encouraged them even when Ms Perovski had told us to stop it.

It was just for fun. I didn't really think anyone could get hurt.

They all jerked their chairs up suddenly. But Ashley's just kept going, sliding out from under him, I think. His head cracked on the window sill behind.

I can still hear it. I had nightmares about it last night.

He wouldn't have jerked up his chair onto its hind legs if I hadn't done it and told them to.

I just wrecked my friend's entire life. What can I ever do to make it up to him?