"The initial defense line," the technician said from behind him, "which protects the village proper, is a series of mounds colored, shaped and surfaced to resemble the Ionian landscape. The fidelity is quite obviously painstaking. Probably made from satellites in orbit around Io. You can easily imagine you're seeing an actual piece of that moon from a distance of ten or more miles up."

The steel ball encountered the perimeter of rough terrain. Its trajectory altered, and the ball wobbled uncertainly, no longer going in any particular direction.

"Deflected," Tinbane said, noting how satisfactorily the contours of the terrain acted to deprive the ball of its descending forward motion. "It's going to bypass the village entirely."

The ball, with severely decreased momentum, wandered into a side crease, followed the crease listlessly, and then, just as it appeared to be drifting into the lower take-up slot, abruptly hurtled from a pressure-cushion and back into play.

On the illuminated background a score registered. Victory, of a momentary sort, for the player. The ball once again menaced the village. Once again it dribbled through the rough terrain, following virtually the same path as before.

"Now you'll notice something moderately important," the technician said. "As it heads toward that same pressure-cushion which it just now hit. Don't watch the ball; watch the cushion."

Tinbane watched. And saw, from the cushion, a tiny wisp of gray smoke. He turned inquiringly toward the technician.

"Now watch the ball!" the technician said sharply.

Again the ball struck the pressure-cushion mounted slightly before the lower take-up slot. This time, however, the cushion failed to react to the ball's impact.

Tinbane blinked as the ball rolled harmlessly on, into the take-up slot and out of play.

"Nothing happened," he said presently.

"That smoke that you saw. Emerging from the wiring of the cushion. An electrical short. Because a rebound from that spot placed the ball in a menacing position – menacing to the village."

"In other words," Tinbane said, "something took note of the effect the cushion was having on the ball. The assembly operates so as to protect itself from the ball's activity." He had seen this before, in other outspacer gambling gear: sophisticated circuitry which kept the gameboard constantly shifting in such a way as to seem alive – in such a way as to reduce the chances of the player winning. On this particular construct the player obtained a winning score by inducing the five steel balls to pass into the central layout: the replica of the Ionian hamlet. Hence the hamlet had to be protected. Hence this particular strategically located pressure-cushion required elimination. At least for the time being. Until the overall configurations of topography altered decidedly.

"Nothing new there," the technician said. "You've seen it a dozen times before; I've seen it a hundred times before. Let's say that this pinball machine has seen ten thousand separate games, and each time there's been a careful readjustment of the circuitry directed toward rendering the steel balls neutralized. Let's say that the alterations are cumulative. So by now any given player's score is probably no more than a fraction of early scores, before the circuits had a chance to react. The direction of alteration – as in all out-spacer gambling mechanisms – has a zero win factor as the limit toward which it's moving. Just try to hit the village, Tinbane. We set up a constantly repeating mechanical ball-release and played one hundred and forty games. At no time did a ball ever get near enough to do the village any harm. We kept a record of the scores obtained. A slight but significant drop was registered each time." He grinned.

"So?" Tinbane said,.

"So nothing. As I told you and as my report says." The technician paused, then. "Except for one thing. Look at this."

Bending, he traced his thin finger across the protective glass of the layout, toward a construct near the center of the replica village. "A photographic record shows that with each game that particular component becomes more articulated. It's being erected by circuitry underneath – obviously. As is every other change. But this configuration – doesn't it remind you of something?"

"Looks like a Roman catapult," Tinbane said. "But with a vertical rather than a horizontal axis."

"That's our reaction, too. And look at the sling. In terms of the scale of the village it's inordinately large. Immense, in fact; specifically, it's not to scale."

"It looks as if it would almost hold -"

"Not almost," the technician said. "We measured it. The size of the sling is exact; one of those steel balls would fit perfectly into it."

"And then?" Tinbane said, feeling chill.

"And then it would hurl the ball back at the player," the lab technician said calmly. "It's aimed directly toward the front of the machine, front and upward." He added, "And it's been virtually completed."

The best defense, Tinbane thought to himself as he studied the out-spacers' illegal pinball machine, is offense. But whoever heard of it in this context?

Zero, he realized, isn't a low enough score to suit the defensive circuitry of the thing. Zero won't do. It's got to strive for less than zero. Why? Because, he decided, it's not really moving toward zero as a limit; it's moving, instead, toward the best defensive pattern. It's too well designed. Or is it?

"You think," he asked the lean, tall lab technician, "that the outspacers intended this?"

"That doesn't matter. At least not from the immediate stand-point. What matters is two factors: the machine was exported – in violation of Terran law – to Terra, and it's been played by Terrans. Intentionally or not, this could be, in fact will soon be, a lethal weapon." He added, "We calculate within the next twenty games. Every time a coin is inserted, the building resumes. Whether a ball gets near the village or not. All it requires is a flow of power from the device's central helium battery. And that's automatic, once play begins." He added, "It's at work building the catapult right now, as we stand here. You better release the remaining four balls, so it'll shut itself off. Or give us permission to dismantle it – to at least take the power supply out of the circuit."

"The outspacers don't have a very high regard for human life," Tinbane reflected. He was thinking of the carnage created by the ship taking off. And that, for them, was routine. But in view of that wholesale destruction of human life, this seemed unnecessary. What more did this accomplish?

Pondering, he said, "This is selective. This would eliminate only the gameplayer."

The technician said, "This would eliminate every gameplayer. One after another."

"But who would play the thing," Tinbane said, "after the first fatality?"

"People go there knowing that if there's a raid the outspacers will burn up everyone and everything," the technician pointed out. "The urge to gamble is an addictive compulsion; a certain type of person gambles no matter what the risk is. You ever hear of Russian Roulette?"

Tinbane released the second steel ball, watched it bounce and wander toward the replica village. This one managed to pass through the rough terrain; it approached the first house comprising the village proper. Maybe I'll get it, he thought savagely. Before it gets me. A strange, novel excitement filled him as he watched the ball thud against the tiny house, flatten the structure and roll on. The ball, although small to him, towered over every building, every structure, that made up the village.

– Every structure except the central catapult. He watched avidly as the ball moved dangerously close to the catapult, then, deflected by a major public building, rolled on and disappeared into the take-up slot. Immediately he sent the third ball hurtling up its channel.