I moved on again.

"Hallo," said a voice. "I saw you get out. How many did you make?"

"None," I said wearily.

"How many?"

I went and sat down next to him.

"Guess," I said.

"Oh, I can't."

"Well, think of a number."

"Yes."

"Double it. Divide by two. Take away the number you first thought of. What does that make?"