"No. Each world must look out for its own. We fought to prevent Earth from despoiling Paleo; we must also fight to prevent other alternates from despoiling us. But we must understand that they are very much like us..."

"Omnivores!" she said bitterly.

"But there is a positive side. Orn's egg has been lost in this alternate -- but there must be many alternates where it was saved. In some you kept it; in others the other Aquilon took it. But the chick isn't dead, there."

"Ornet," she said. "Offspring of Orn and Ornette..."

He smiled. She was coming out of it. "By any other name... Now we must find out what happened to Veg."

Her eyes followed the tracks across the sand. "Do you think he -- ?"

"I sent the mantas after him. Somehow they know; they would not have gone if he were dead."

"Yes, of course," she murmured.

They cleaned up the supplies somewhat, making packs for each person, just in case. A blaster and a rifle were missing, and one of the long crowbars, suggesting that Veg had taken them. "But we already know that we face a strange situation," Cal warned her. "Conventional weapons may be useless."

"Machine!" she said suddenly.

Cal looked up inquiringly. "We have no machines here."

"My double -- she said something about machines, here in the desert. 'Awful machines.' A danger -- "

Cal looked once more at the tread-tracks. "A machine," he murmured thoughtfully. "Following Veg..."

"Oh, let's hurry!" she cried. "And take weapons!"

They started out warily, following Veg's tracks and those of the mystery vehicle. Cal was ill at ease; if a human being could appear from another alternate, so could heavy equipment. Suppose some kind of tank had been dispatched to hunt down the visitors to this world? They just might have walked into an interalternate war...

Aquilon stopped abruptly, rubbing her eyes. "Cal!" she whispered.

Cal looked. At first he saw nothing; then he became aware of a kind of sparkle in the air ahead. Faint lights were blinking on and off, changing their fairy patterns constantly.

"A firefly swarm?" Aquilon asked. "Let me paint it." She was never without her brush and pad, and now, without the egg to hold, she could paint again.

She hesitated. He knew why: Her sudden freedom made her feel guilty. How much better to have given the egg to her double! The woman would have taken care of it every bit as well as Aquilon herself because she was Aquilon -- wiser for her bitter experience. Or at least, so it would seem -- to this Aquilon at this moment. He had to divert her thoughts.

"Fireflies? With no plants to feed the insects?" Cal asked, posing what he knew to be a fallacious question. "We have seen no indigenous life here."

"There has to be life," she replied as she quickly sketched. "Otherwise there would be no breathable atmosphere. Plants give off oxygen."

"Yes, of course..." he agreed, watching the swarm. "Still, there is something odd here."

The sparkle-pattern intensified. Now it was like a small galaxy of twinkling stars, the individual lights changing so rapidly that the eye could not fix on them. But Aquilon's trained perception was catching the artistry of it. Color flowed from her automatic brush, brightening the picture. This was the marvelous, creative person he had known, expressing herself through her art.

The flashes were not random; they moved in ripples, like the marquee of an old cinemahouse. These ripples twined and flexed like living things. But not like chains of fireflies.

"Beautiful," Aquilon breathed. Yes, now her own beauty illumined her; she was what she perceived.

Suddenly the swarm moved toward them. The lights became bright and sharp. The outline expanded enormously.

"Fascinating," Cal said, seeing three-dimensional patterns within the cloud, geometric ratios building and rebuilding in dazzling array. This was no random collection of blinkers...

Aquilon grabbed his arm. "It sees us!" she cried in abrupt alarm. "Run!"

It was already too late. The glowing swarm was upon them.

Chapter 2.

OX.

Survive!

OX a.s.similated the directive, knowing nothing but the need. How, why, mode, were absent; there was no rationale. Only the imperative. It was inherent in his being; it made him what he was. It was what he was: the need to survive.

He turned his attention to the external.

Disorientation. Distress. Nonsurvival.

OX retracted, halving his volume. What had happened?

Survival dictated that he explore despite the pain of the external. OX realized that through DISTRESS related to NONSURVIVAL, certain forms of distress might be necessary to survival. Judgment was required. He modified his capabilities to accommodate this concept and thereby became more intelligent.

Experiment and intelligence provided a working rationale: He had extended himself too precipitously and thereby thrown his basic organization out of balance.

The lesson: Expansion had to be organized. Four dimensions became far more complex than three, requiring a different type of organization.

OX extended a fleeting outer feedback sh.e.l.l to explore the limits of his locale. It was not large; he had room to move about but had to contain himself somewhat.

Discomfort. Minor distress but growing. OX hovered in place, but the discomfort increased. He moved, and it abated. Why?

The base on which he rested, the network of points, was fading. He was his environment; he occupied many small elements, drawing energy from them, making a sentient pattern of them. This energy was limited; he had to move off and allow it to regenerate periodically. Merely sitting in one spot would exhaust that set of elements: nonsurvival.

The larger OX expanded, the more points he encompa.s.sed and the more energy he consumed. By contracting within optimum volume he conserved survival resources. But he could not become too small, for that limited his abilities and led to dysfunction.

OX stabilized. But his minimum functional size was still too large for the territory to sustain indefinitely. He could exist at maximum size briefly or at minimum size longer -- but the end was nonsurvival, either way.

Survive! He had to keep searching.

He searched. Unsuccess wasted resources and led to discomfort. Yet even in his distress, there was a special irritant. Certain circuits were not functioning properly. He investigated. All was in order.

He returned to the larger problem of survival -- and the interference resumed persistently.

OX concentrated on the annoyance. Still there was no perceivable dysfunction. It did not manifest when he searched for it, only when he was otherwise occupied.

He set up a spotter circuit, oriented on the troublesome section. He had not known how to do this before the need arose, but this was the way of survival: the necessary, as necessary.

OX returned to his larger quest -- and the irritation manifested. This time the spotter was on it. He concentrated, pouncing, as it were, on what he had trapped.