CU: Rules

When God rolls the dice, he's not playing games.

—Arjun

The artifact's game made chess and Go look like child's play. While the rules were simple, the possible permutations exceeded the number of atoms in the universe. It was based on three-dimensional cellular automata, which Sanjay patiently explained to the rest of the team.

"Picture a three-by-three cube like one of those Rubik's cubes from the twentieth century. Now picture the hidden cube in the center. We'll call this the home cube. It shares a side, an edge, or a corner with the twenty-six outside cubes, which we'll call neighbors. You define a simple set of rules whereby the home cube causes the colors of its neighbors to flip in a particular pattern. There are three colors—neutral silver, red, and blue—and three possible flip behaviors: flip red if blue, flip blue if red, and flip to opposite color or random if neutral. If offsetting flips act on a cube, it reverts to neutral. A simplistic pattern would be to flip all left neighbors to red if blue and all right neighbors to blue if red."

"Sounds boring," Misuni said. "Where's the sexy in that?"

"The sexy part is what happens next," Sanjay said. "Once the home cube has taken its turn, any of the twenty-six neighboring cubes you designate—you can choose all, none, or any combination—now become home to their own cube and apply the flip pattern all over again. Then the chosen neighbors become home cubes and so on for the specified number of moves. Meanwhile, your opponent is playing his own pattern, trying to counter yours. There are eleven rounds in a game with each round increasing by eleven moves, or cube-steps. The final round has a hundred and twenty-one moves, more than enough to wrap around the entire board. At the end of the game, the side with the most color points wins."

Though the rules were simple, the resulting gameplay was fiendishly complex. The simplest approach was to flip as many squares as possible to one's own color, but that left easy pickings for the other side. Furthermore, the random flip behavior of the neutral squares thwarted brute force prediction. One had to not only determine the interactions of one's own patterns but those of one's opponent as they reversed or neutralized each other. With roughly fourteen minutes allowed per round there was little time to work out the complex permutations. The game began with a random flip of half the points.

"All right, Jaine, are you ready to teach this wirehead a lesson in game theory?" Arjun said.

"My algorithms are not optimized for high-speed adversarial simulations using quasi-deterministic probability matrices."

"You can navigate a ship across trillions of miles of pure vacuum but can't play fancy checkers?" Arjun scoffed. "Fine then. If not you, who else?"

"My gamemaster AI," Sanjay said. "I take it on time-slips with me to keep my ultra-chess skills sharp. I'm rated a grandmaster myself, but I've never once come close to beating it."

"How about that? All this time we've had a stowaway AI on board. You really think this gamemaster stands a chance against this thing?"

"I can divert some of the ship's compu-flops," Jaine said, "and the physics personais can offload the calculations."

"How long will that take?"

"As long as it takes to say AlphaGo."

Xemesh: Division and Propagation

Unification is the weapon of monarchs. Division is the weapon of rebels. Fickleness is the weapon of the people.

—Arjun

The clash of two Xemesh sparked a burst of intense competition. The battle was over mineral resources. The volcanic age that spewed out the planet's molten guts had long since subsided, and millions of years of weathering and regrowth had buried or carried off most of the surface deposits. When the swamp and forest Xemesh encountered each other, they did not perceive a kindred species but only a mineral bounty to be exploited.

Neither side held a winning advantage. The forest-Xemesh was much larger, but the swamp-Xemesh was tightly concentrated, making it easier to defend and quicker to mount a response. The forest-Xants could not survive underwater while the swamp-Xants were poor climbers. The forest-Xemesh held the high ground and possessed superior numbers, but the swamp-Xemesh had the raiders' advantage of mobility and surprise.

Millennia passed as each side honed its tactics and armaments. It was during this time that the Xemesh gained the ability to divide and propagate. Responding to violent floods full of treacherous debris, the swamp-Xemesh figured out how to disassemble itself into smaller clusters that could be reunified in calmer waters. In battle, this ability found a new use. Through division, the swamp-Xemesh could attack along multiple points, creating diversions and sowing confusion in the enemy. But separation came at a risk; each part lacked the cunning and force of the whole, leaving them vulnerable to counterattack. And there was always the chance they might become separated for good, an outcome which became all but inevitable as the segments ranged further apart.

Nonetheless, the tactic was so effective that the forest-Xemesh was forced to respond in kind lest it be slowly carved away. Its best defense was to subdivide into semi-autonomous units. By relieving congestion and reducing the distance messages had to travel, the local mesh could respond quicker to threats and, in the case it was overrun, cordon off the damage. Regionalization triggered a new era of expansion as each sub-unit sought to grow to its full potential. When one sub-unit chanced upon a mineral-rich ravine, it went on a building frenzy, becoming so large it halved and then halved again.

Meanwhile, unaware of this development, the swamp-Xemesh made a series of incursions that left it overextended. Before it could react, the resurgent forest-Xemesh obliterated two of its five segments. Hard beset, the remaining segments only barely managed to break free and reunite.

While the forest-Xemesh had scored a major victory, the conflict was far from over. Protected by miles of turgid moat, the swamp-Xemesh set about rebuilding its strength. Unable to challenge the forest-Xemesh, it turned its attention in the opposite direction to the rising plains that, at first prospect, seemed barren and uninviting. Here it chanced upon the rock-Xemesh.