Hex snapped twice.

"I think you should look at the tracks," Tamme said. "Something strange is going on, and we may be in danger." Understatement of the day!

"Wait," Veg said. "The mantas came across with Cal, right? They must know." But as he spoke, he saw that Hex was ignorant of the matter.

Tamme shrugged. "I guess that Cal found you missing, so he sent them to find you. While they were gone, something got him." She perceived his new alarm and quickly amended her statement. "He's not dead so far as I know. He's just gone. The tracks walk out into the sand and stop. I suspect a machine lifted him away."

"A flying machine?" He pondered. "Could be. I didn't see it -- but that ground machine sure was tough. But if -- "

"I don't think it ate them," Tamme said, again picking up his specific concern. He had strong ties to his friends! "There's no blood in the sand, no sign of struggle. The prints show they were standing there but not running or fighting."

"Maybe," he said, half relieved. "Hex -- any ideas?"

Three snaps.

"He doesn't know," Veg said. "Circe must be looking for them now. Maybe we'd better just go back to camp and wait -- "

Tamme reached out, took his arm and hauled him to the side with a strength he had not suspected in her. They sprawled on the ground behind a boulder. Wordlessly, she pointed.

Something hovered in the air a hundred feet ahead. A network of glimmering points, like bright dust motes in sunlight. But also like the night sky. It was as though tiny stars were being born right here in the planet's atmosphere. She had never heard of anything like this; nothing in her programming approached it.

Hex jumped up, orienting on the swarm. He shot toward it.

"Watch it, Hex!" Veg cried.

But Tamme recognized a weakness in the manta. The creature had to be airborne to be combat-ready. Actually it stepped across the ground rapidly, one-footed, its cape bracing against the pressure of the atmosphere. It had to aim that big eye directly on the subject to see it at all. Thus, the manta had to head toward the swarm -- or ignore it. Probably the creature would veer off just shy of the sparkle.

Hex did. But at that moment the pattern of lights expanded abruptly, doubling its size. The outer fringe extended beyond the manta's moving body. And Hex disappeared.

So did the light-swarm. The desert was dull again.

"What the h.e.l.l was it?" Veg exclaimed.

"Whatever took your friends," Tamme said tersely. "An energy consumer -- or a matter transmitter."

"It got Hex..."

"I think we'd better get out of here. In a hurry."

"I'm with you!"

They got up and ran back the way they had come.

"Circe!" Veg cried. "There's something after us -- and don't you go near it! It got Hex!"

"Oh-oh," Tamme said.

Veg glanced back apprehensively. The pattern was there again, moving toward them rapidly. Circe came to rest beside them, facing it.

"We can't outrun it," Tamme said. "We'll have to fight."

She faced the swarm, trying to a.n.a.lyze it for weakness, though she did not know what she was looking for. The thing swirled and pulsed like a giant airborne amoeba, sending out fleeting pseudopods that vanished instead of retracting. Sparks that burned out when flung from the main ma.s.s?

"G.o.d..." Veg said.

"Or the devil," she said, firing one hip-blaster.

The energy streamed through the center of the bright cloud. Points of light glowed all along the path of her shot, but the swarm did not collapse.

"It's a ghost!" Veg said. "You can't burn a ghost!" He was amazed rather than afraid. Fear simply was not natural to him; he had run as one might from a falling tree, preserving himself without terror.

Tamme drew another weapon. A jet of fluid shot out. "Fire extinguisher," she said.

It had no effect, either. Now the swarm was upon them. Pinpoint lights surrounded them, making it seem as though they stood in the center of a starry nebula. Circe jumped up, her mantle spreading broadly, but there was nothing for her to strike at, and it was too late to escape.

Then something strange happened.

Chapter 4.

SENTIENCE.

First problem: survival in a nonsurvival situation.

Second problem: existence of mobile blight, detectable only by its transitory damping effect on elements.

Each problem seemed insoluble by itself. But together, there was a possibility. The existence of mobile nonpattern ent.i.ties implied that a nonpattern mode of survival was feasible. Comprehend the mode of the blight, and perhaps survival would develop.

OX's original circuitry had difficulty accepting this supposition, so he modified it. The nagging distress occasioned by these modifications served as warning that he could be pursuing a nonsurvival course. But when all apparent courses were nonsurvival, did it matter?

He put his full attention to the blight problem. First he mapped the complete outline of each blight spot, getting an exact idea of its shape. One was virtually stationary, a central blob with extensions that moved about. Another moved slowly from location to location in two dimensions, retaining its form. The third was most promising because it moved rapidly in three dimensions and changed its shape as it moved.

This was the way a sentient ent.i.ty functioned.

Yet it was blight. A mere pattern of element damping.

Pattern. A pattern of blight was still a pattern, and pattern was the fundamental indication of sentience. Thus, nonsentients were sentient. Another paradox, indicating a flaw in perception or rationale.

Possibility: The blight was not blight but the facsimile of blight. As though a pattern were present but whose presence suppressed the activation of the elements instead of facilitating it. An inverse ent.i.ty.

Error. Such an ent.i.ty should leave blanks where those elements were being suppressed: as of the absence of elements. OX perceived no such blanks. When he activated given elements, the presence of an inverse pattern should at least nullify it so that the elements would seem untouched. Instead, they did activate -- but not as sharply as was proper. The effect was more like a shield, dimming but not obliterating the flow of energy. A blight, not a pattern.

OX suffered another period of disorientation. It required energy to wrestle with paradox, and he was already short of the reserve required for survival.

In due course he returned to the problem; he had to. It seemed that the ultimate nature of the spots was incomprehensible. But their perceivable attributes could be ascertained and catalogued, perhaps leading to some clarification. It was still his best approach to survival. Where a pseudopattern could survive, so might a genuine pattern.

OX developed a modified spotter circuit that enabled him to perceive the spots as simple patterns rather than as pattern-gaps. The effect was marvelous: Suddenly, seeming randomness became sensible. Instead of ghosts, these now manifested as viable, if peculiar, ent.i.ties.

The most comprehensible was the outline-changing spot. At times it was stationary, like a pattern at rest. When it moved, it altered its shape -- as a pattern ent.i.ty normally did. But even here there was a mystery: The spot did not change according to the fundamental rules of pattern. It could therefore not be stable. Yet it was; it always returned to a similar configuration.