"I don't know which one I am, or if this is the first time I've written this note," the paper said. "All I know is that I think someone is following me.""Yes." I said to the note. "I am."I crumpled it in my hand. "And we've done this before."I tore the note into tiny pieces and put most of them in my pocket and some into the trashcan next to the end of the row of lockers. I would throw them away in three different cans later. You couldn't be too careful. I used to burn them, but sometimes these places had sensors. Burning things just got people to ask questions you didn't want to answer.