Rodgers was looking round for a new victim.
"What does the thing do?" I asked.
"It's a modification of naughts and crosses—what the Americans call Tic-Tac-Toe. Shannon showed it to me when I was over at Bell Labs. What you have to do is to complete a path from one side of the board to the other—call it North to South—by turning these switches. Imagine the thing forms a grid of streets, if you like, and these neons are the traffic lights. You and the machine take turns making moves. The machine tries to block your path by building one of its own in the East-West direction—the little neons light up to tell you which way it wants to make a move. Neither track need be a straight line: you can zig-zag as much as you like. All that matters is that the path must be continuous, and the one to get across the board first wins."
"Meaning the machine, I suppose?"
"Well, it's never been beaten yet."
"Can't you force a draw, by blocking the machine's path so that at least you don't lose?"
"That's what we're trying; like to have a go?"
Two minutes later I joined the other unsuccessful contestants. The machine had dodged all my barriers and established its own track from East to West. I wasn't convinced that it was unbeatable, but the game was clearly a good deal more complicated than it looked. Eric glanced round his audience when I had retired. No one else seemed in a hurry to move forward.
"Ha!" he said. "The very man. What about you, Purvis? You've not had a shot yet."
Harry Purvis was standing at the back of the crowd, with a faroff look in his eye. He jolted back to earth as Eric addressed him, but didn't answer the question directly.
"Fascinating things, these electronic computers," he mused. "I suppose I shouldn't tell you this, but your gadget reminds me of what happened to Project Clausewitz. A curious story, and one very expensive to the American taxpayer."
"Look," said John Wyndham anxiously. "Before you start, be a good sport and let us get our glasses filled. Draw!"
This important matter having been attended to, we gathered round Harry. Only Charlie Willis still remained with the machine, hopefully trying his luck.
"As you all know," began Harry, "Science with a capital S is a big thing in the military world these days. The weapons side—rockets, atom bombs and so on—is only part of it, though that's all the public knows about. Much more fascinating, in my opinion, is the operational research angle. You might say that's concerned with brains rather than brute force.
