# Schild`s Ladder 7

Иган Грег

If their mimicry of the signaling layer produced a promising reaction, they would move on to more complex exchanges, playing it by ear, hoping that the banner itself would prompt their hosts to respond in kind. Nothing the probes had revealed had offered any clues about the Colonists' preferred mode of interpersonal communication; sprites and other potential information-carriers flooded the colony, but plucking messages in an unknown language from all the influences modulating these carriers was beyond the standard Mediator software they"d brought through the border. Given time, Tchicaya would have happily observed the Colonists from a distance until everything about them, right down to the subtlest cultural nuance, was absolutely clear. He and Mariama could have descended from the sky expecting compliments on their perfect local accents and unprecedented good manners, like a pair of conscientious travelers.

It was not going to happen that way. The coming of the Planck worms would be unheralded, but the five percent error bars of the toolkit"s best statistical guess had already been crossed. If the sky rained poison right now, as they rushed through their rudimentary preparations, they would not even have the bitter consolation of knowing that they"d been ambushed by unforeseeable events.

They"d reached the end game, ready or not. They"d have to walk a knife edge between recklessness and caution, but they could not afford to take a single step back.

The signaling banner spiraled down toward the colony, twisting and fluttering like an airborne tent in a hurricane, but pulsing steadily from translucent to opaque. The Sarumpaet followed, close enough to maintain a probe image of the banner that was only a fraction of a ship-second out of date. The probes could also ferry instructions from the ship to the banner, enabling the signal to be modified on a similar time scale as soon as the need arose.

From the deck of the Sarumpaet, Tchicaya formed a rapid series of impressions of the crowded world below, none of which he believed was worth trusting. The density and animation of the creatures made him think of the bustle of markets of festivals, of riots. Of the crew of some ancient, oceangoing vessel battling a storm. In fact, all this violent swaying in the wind was probably about as exciting for the Colonists as a terrestrial animal"s endlessly beating heart. For all he knew, this was what they looked like at their most indolent.

He searched for any hint of a flickering shadow from the banner on the surface below, but between the shimmering of the sprites and the erratic geometry of all the objects involved, that was too much to expect. Perhaps it was fortunate that the nearsiders would not arrive with anything like the drama of an artificial eclipse; even if these xennobes did belong to the same species as the Signalers, different cultures could still have varying degrees of sophistication, and an overblown spectacle might have terrified a group for whom the search for life beyond the border was a barely comprehensible endeavor, something that only an obscure, deranged minority would even contemplate.

On the other hand, since the banner had no significant effect on the ground, it was possible that no one would even notice it. It wasn"t clear that any of the Bright"s inhabitants focused the sprites to form an image; the rabbit had been close enough to the banner it attacked to sense its presence through a drop in overall irradiation, like a chill on the skin. It made evolutionary sense to expect all mobile xennobes to possess a detailed knowledge of their surroundings, but a sufficiently unnatural object might still be as invisible to them as a burst of neutrinos to a human.

The banner came to a halt at a predetermined altitude: some twenty times the Colonists' typical body size. Tchicaya gazed down at the crowd, wondering how he was going to distinguish panic from indifference. The Colonists weren"t as shapeless as the airflowers; their network of vendek tubes bifurcated twice to give four distinct clusters of branches, and their geometry at any moment tended to reflect this. They looked like medical scans of the circulatory system of some headless quadruped, dog-paddling ineffectually in extremely rough seas. But if that intrusive probe image was unlikely to reflect the way they saw each other, by sprites alone they resembled tortured, mutilated ghosts, trying to break through into the world of the living.

Mariama said, "I think it"s been noticed."

"Where?"

She pointed; a group of six Colonists had left the surface. As Tchicaya watched, they ascended rapidly, but as they grew nearer to the banner they slowed considerably. This cautious interest was not proof of anything, but it was an encouraging sign.

The Colonists surrounded the device, then began spraying it with a delicate mist of vendeks. "That"s cooperative sensing!" Mariama exclaimed. "One of them illuminates the object, the other looks at the transmitted pattern."

"I think you"re right." The group was arranged in pairs on either side of the banner, and the members of each pair took turns emitting the vendeks. The probes hadn"t encountered this species of vendek before; perhaps nothing inside the colony warranted the same kind of scrutiny as this alien object.

The Colonists retreated and formed a loose huddle away from the banner. "What now?" Tchicaya wondered. "How do you react to a mutated version of your own stratospheric beacon suddenly appearing on your doorstep?"

Mariama said, "I just hope they realize they don"t need to launch a new signaling layer in order to reply."

"Maybe we should try to make a more obvious proxy," he suggested. "Something that resembles one of their bodies."

"How would we decide which features to include, and which to leave out? We don"t even know the difference between their communications signals and their waste products. We"d probably come up with the equivalent of a glove puppet of a monkey that smelled exactly like human excrement."

She had a point; even the six Colonists high above the din - and/or stench - of the colony were now bathed in a confusing fog of vendeks, and it was beyond the Sarumpaet's resources to untangle their functions and meaning.

Tchicaya felt a sudden stab of pessimism. He believed he"d finally reached the people he"d come to find - but he had days, at most, not only to describe the Planck worms to them, but to reach a level of communication and trust that would enable them to work together to deal with the threat. However many subtleties, abstractions, and courtesies he omitted along the way, even conveying the core of the message was beginning to seem hopelessly ambitious.

He said, "Maybe we should change the signal right now, instead of waiting for them to reply? Just to make it clear that the banner"s not passive?"

Before Mariama could respond, the Colonists began regrouping around the banner. In unison, they released a stream of vendeks, denser than before; in the probe image, it looked as if the six veined bodies were blowing soap films. The individual sheets met at the edges and merged, forming a bubble, enclosing the banner.

The Colonists retreated again, then sprayed a new mixture at the bubble. It began to drift after them, down toward the surface.

Mariama said, "They"ve grabbed it! They"re towing it!"

The wall of the bubble was passing sprites, but it resisted the Sarumpaet's probes - the only means they had to get instructions to the banner. They"d lost control of the device completely, now; they couldn"t even reprogram its message, let alone command it to try to break out of its cage.

"We could make another one," Tchicaya suggested. "Right in front of their eyes."

"Why not see what they do with this one?"

"You think we should follow it?"

Mariama nodded. "They might release it from the container, once they"ve got it where they want it. They might even have their own signaling device down there."

Tchicaya was not convinced. "If they think it"s just a message in a bottle, they"re not going to talk back to it. And if we can"t regain control of it, the last place we want to try scribing a new one is in the middle of some chamber down there."

"We"ll only find out what they think it is if we go after it," Mariama replied. "Besides, we initiated contact with this object. We should stick to that, follow through with it, or we risk confusing them."

That did make sense. They had to be flexible, or they"d end up chasing their preconceptions down a cul-de-sac, but they also had to try to be consistent. Changing tack every time they feared that they might have been misinterpreted could bury any message beneath all the distracting shifts in strategy.

Tchicaya said, "All right, we"ll follow it!" He instructed the Sarumpaet to pursue the purloined banner.

As they descended, it finally struck him just how extraordinary a sight they were witnessing. The banner was still flashing out its programmed sequence from within its container; the Colonists hadn"t damaged it at all. Towing anything without destroying it, here, was a feat akin to putting a tornado on a leash. There were no simple analogs of the notions of pushing or pulling something, let alone any reason to expect it to respond by moving as a whole - like a nice near-side object made from atoms bonded together into a mildly elastic solid. You couldn"t even rely on the local physics to permit something to behave, in uniform motion, as it had when it was stationary, however gently you conveyed it from one state to the other.

He turned to Mariama. "This is proof, isn"t it? They have to be more than animals, to be able to move it like that."

Mariama hesitated, no doubt pondering the evolutionary advantages of a delicate touch when kidnapping other species of xennobe to fill with your parasitic young.

But she said, "I think you"re right. I"ve been giving them the benefit of the doubt until now, but I think they"ve finally earned it."

The six Colonists touched down on the surface and proceeded along a narrow path that opened up in the throng ahead of them. The bubble appeared to be following a vendek trail laid by its creators, and the Sarumpaet stayed close enough behind it to avoid the crowd as it reclaimed the ground in the wake of the procession. Rather than rendering the flight deck in proportion to the ship"s actual physical dimensions, the scape was constantly making choices of scale to keep the view of their surroundings intelligible, and the Colonists on either side of the ship appeared roughly as large as giraffes. Absurd as it was, Tchicaya found it difficult to suppress the feeling that they might look in through the hull and see him standing on the deck gazing back at them; he kept wanting to avert his eyes, so as not to risk frightening or provoking them.

Close up, the ship"s probes revealed more of the Colonists' anatomy. Dwelling on the crude, wind-blown X of their overall shape was pointless; everything that mattered was in the vendek mixtures locked in the network of tubes. The toolkit struggled to annotate the images, hinting at the subtlety of the vendekobiology and the complexity of the network"s topology. Tchicaya could only take in a fraction of what the toolkit was managing to glean, but the Colonists were manipulating their internal physics with as much precision as any animal controlling its biochemistry, juggling pH or glucose concentrations.

He caught Mariama"s eye, and the two of them exchanged giddy, fearful smiles. Like Tchicaya, she was enraptured by the beauty and strangeness around them, but more painfully aware than ever of the vast gulf they"d have to bridge in order to protect it. The closer they came to the possibility of success, the more vertiginous the fall if they lost their grip. To be overrun by Planck worms in the honeycomb would have meant nothing but a bleak local death; here, they would be witnessing a whole world dying.

The procession entered a tunnel, angled steeply down into the colony"s interior. As the density of sprites dropped, the scape experimented with the other ambient information-carrying vendeks. No single species could come close to matching the details of the probe images, but taken together they provided a fair description of the surroundings. From the Colonists' point of view, the Bright might well have been horribly misnamed; the conditions down here stood a far better chance of providing useful illumination, and the colony could have been perceived to lie in a somber landscape of permanent twilight.

Out of the full force of the wind, the geometry of both the Colonists and their architecture became more stable. The walls of the tunnel were formed from a basic layer population, but hundreds of other structures adorned them. Apart from the "air-conditioning" and "light sources," Tchicaya couldn"t guess what purpose most of the structures served. They looked too complex to be decorations, but mere endurance required sophistication here; the air-conditioning wasn"t perfect, and anything incapable of responding to the weather risked being scoured away by the Bright.

The tunnel branched; the procession veered left. The air-conditioning was becoming more aggressive about removing impurities; the ship and the toolkit had to work harder than ever to keep the hull intact and the probes viable in the presence of all the new cleaning vendeks. Tchicaya had contemplated a number of unpleasant fates since the anachronauts had blown him out of the Rindler, but being scrubbed from the environment like an unwelcome speck of dust was one of the most insulting.

After a second fork, and a section that zigzagged and corkscrewed simultaneously, the tunnel opened out into a large cave. The physics here was more stable than anything they"d seen since the honeycomb; the weather had not been banished, but the turbulence had been subdued by an order of magnitude compared to the open Bright.

A stream of vendeks crossed the cave, rendered pitch black by the scape for most of its length, where the probes found it impenetrable. Near the center, the stream mingled with the surrounding free vendeks, expanding and becoming diluted before contracting back to its original width and continuing on its way. The probes could enter this region, which they portrayed as a sphere of gray fog; not all of them were coming back, though, and those that did reported that they"d almost lost control over their trajectories. Moving through the Bright had been difficult from the start, but some extreme, systematic distortion here was interfering with their attempts to navigate.

The toolkit collated all the evidence and reached its own conclusion. "There"s curvature engineered into the graphs here. You can invade these vendeks where the current opens out, but in the process they reorient your time axis."

It took Tchicaya a moment to digest this. Patterns in a quantum graph persisted by replicating themselves in future versions of the graph, but "the future" could only be defined by the orientation of the pattern itself. If you sliced the space-time foam one way to find a graph with vendek A in it, but needed to take a slice at a different angle to find vendek B, the two vendeks would see time as lying in different directions, and mere persistence, on their own terms, would put them in relative motion.

So "reorient your time axis" was toolkit-speak for "change your velocity." The vendek current couldn"t sweep anything along the way a river did, with pressure and momentum, but it could twist the local definition of being "stationary" progressively further away from its original orientation. In a sense it was like ordinary gravity, but on the near side the symmetries of the vacuum imposed a rigid austerity on the possibilities for space-time curvature. Here, the curvature had been tailored on the spot, woven directly into the graphs by the choice of vendeks.

"These people engineer space-time the way we do polymer design," he marveled. "Choose the right monomers, get their shape and reactivity right, and you can create whatever properties you desire."

Mariama smiled. "Except that they"re more like microbes than monomers. Everything comes down to breeding and blending the right vendeks."

"So what is this? A waste-disposal system?" If they wanted to toss the banner away, they could have done that from the surface with their towing bubble, but this accelerated sewer might send it further, faster.

The Colonists had paused at the entrance to the cave, but now they began to move along a shallow spiral, inching their way down toward the velocity gradient. They weren"t discarding the banner in the black river. They were going with it.

Tchicaya groaned. "I know what this is! We saw the rest of it, from the outside. It"s a transport system. We"re on the entry ramp to a highway."

Mariama agreed. "Maybe this whole place is just a tiny outpost, and the artifact is such a big deal that they"re rushing it straight to the nearest expert."

The conga line of Colonists was winding its way toward the axis of the cave, actively fighting the effect of the black vendeks in order not to get dashed against the wall where the current exited. The Sarumpaet was still obediently following the towing bubble; if they wanted to break away from the convoy, they"d have to do it in the next few seconds.

There was no way of knowing how long the journey would take. They"d seen this highway disappearing into the haze, into the depths Xof the far side. This outpost was where the danger would strike first, where the people needed to be told what was coming so they could fight it, or evacuate.

But if the banner was being taken to the Signalers themselves, that could be the expedition"s one opportunity to meet people with the knowledge and motivation needed to understand the warning at all.

Mariama said, "You don"t want to back out?" Perhaps she was afraid that if this turned out to be the wrong choice, he"d hold her responsible for urging him down here in the first place.

Tchicaya said, "No. We have to trust these people to take us to someone who"ll work hard to communicate with us. If that"s not what they"re planning, then we"re screwed - but if we hang back and miss the chance to meet the experts, we"re screwed anyway." Ahead of them, the banner was blinking feebly; undamaged still, but it had never been designed to modulate all the forms of illumination that filled the cave.

The bubble arced smoothly down into the gray fog of the entry ramp. As they followed it, the fog around them actually seemed to grow thinner; once the Sarumpaet began to surrender to the highway"s demands, the probes had an easier task finding their way back to it - though the rest of the cave rapidly vanished from sight. Tchicaya felt a pang of frustration that he was insulated from any sense of the dynamics at play here. What would it feel like, for a native, to be whisked into motion like this? Would there be something akin to tidal effects, as different parts of your body were brought up to speed? It was a trivial thing to ponder, but he needed to cut through the barriers that separated him from the Colonists. He needed to imagine himself inside their skins, any way he could.

The convoy straightened out. They were in the center of the highway now, portrayed by the probes as a narrow tube of clarity surrounded by fog. The Colonists themselves had begun emitting some of the parasprites that had illuminated the tunnels and the cave; the bubble and its cargo blocked the view ahead, but Tchicaya could still catch glimpses of them, shy luminescent starfish waving their four legs lethargically. They were probably relaxing, free from the arduous demands of the Bright - or if those demands were trivial, perhaps this trip was so dull for them that they"d entered something close to suspended animation. The Sarumpaet was doing absolutely nothing to keep up with them; as far as it was concerned, everyone was motionless. The highway had them all free-falling effortlessly toward their destination.

Mariama asked the toolkit, "Can you tell how fast we"re moving?"

"I have no direct access to the Bright around us, and interpreting the acceleration process we"ve just been through is difficult."

"Don"t be such a killjoy; take a wild guess. In the broadest, most naive, near-side terms."

"We might be doing something comparable to relativistic speeds."

Mariama looked around the scape, her eyes shining. "Do you remember what Rasmah said?" She was addressing Tchicaya now. "When she spoke to the Preservationists before the moratorium vote?"

"Of course." Tchicaya had to make a conscious effort to summon up the memory, but he"d had a few other things on his mind.

"She was right," Mariama declared. "Her whole vision of this place was exactly right. Not in the details; she couldn"t anticipate half the things we"ve seen here. But she understood precisely what the far side could mean for us."

Tchicaya experienced a twinge of irritation, bordering on jealousy. What right did she have to share Rasmah"s vision? He was ashamed of himself immediately; she"d earned it, at least as much as he had.

"You"ve had a change of heart," he observed mildly.

"I told you I"d never fight for an exotic wasteland," she said, "but that"s not what this is. And I"ll fight for the Signalers because they deserve our help, but that"s not the end of it. Not anymore."

She took Tchicaya"s hands. "Some astronomically rare event created sentient life on the other side of the border, but that"s all it was: bad luck, an accident of birth. We"ve found ways to live with all the hardships: the distance, the loneliness. That"s a great achievement, an amazing feat, but that"s no reason to sentence ourselves to repeat it for eternity.

"How can we go on living in that wasteland, when even space is alive here? This is where we belong, Tchicaya. I"ll fight for this place because it"s our home."

In the eerie calm of the highway, Tchicaya felt himself losing his grip on reality. A whole universe was at stake, and here he was playing stowaway on a road train? Unknown multitudes would die, because he lacked the nerve to tap the driver on the shoulder and make his presence known. He could get his message across to anyone, if he put his mind to it. He"d managed to converse with twenty-third-century zealots with flesh for brains; how much harder could a glowing starfish be?

When the highway began to disgorge them after barely two hours, he almost wept with relief. His gamble might yet fail to pay off, but at least it hadn"t irrevocably sunk the whole endeavor.

As they spiraled out of the darkness, the Sarumpaet steeled itself for the worst contingencies the toolkit could imagine. The Bright had been a challenge, but there was no reason to believe that it was the most extreme environment the far side could contain.

Probes began returning. Parasprites flooded in. The convoy slipped out of the ramp into a vast, tranquil space. The toolkit analyzed the vendeks around them; the mixture was not honeycombstable, but it was like the Bright tamed, domesticated. The airconditioning in the colony had gone a short way in the same direction, but it was like the difference between a mesh cage in the open ocean, keeping the largest predators at bay, and an aquarium of hand-picked species that could coexist and thrive with a minimum of drama.

The six Colonists were not alone here; the scape showed hundreds of similar four-branched xennobes moving around them in a multitude of neat, loosely defined rows, as if the place was crisscrossed with invisible escalators. Compared to the crush of the outpost, though, conditions were far from crowded. Layer walls undulated gently in the distance, dotted with parasprite lamps, but there was none of the density of structure they"d seen in the tunnels. High above Tchicaya - "above" according to the random orientation in which the Sarumpaet had emerged - other dark highways were visible.

"I believe we"re in a railway station," he said. "The question is, where?"

Mariama declared confidently, "This is the big smoke. All space and comfort."

"Where we came from wasn"t exactly a ghost town."

"No, just a small village with no entertainment, and no contraception."

Tchicaya scowled, but then he realized that she was being neither serious nor entirely flippant. Tossing a few anthropomorphic parodies at the least important of the ten thousand unanswered questions they faced might at least stop them wasting energy trying to fill in the same blanks with earnest hypotheses that were just as likely to be wrong.

As the Colonists crossed the atrium, alien cargo and its wouldbe puppeteers in tow, Mariama mimed cracking a whip. "Take me to your linguists," she said. "And don"t spare the vendeks."

If they were in a city, they had no way of judging its size from within, no way of knowing if they were moving from building to building through something like open air, or merely navigating through the rooms of a single, vast, hermetically sealed structure.

They passed through narrow apertures and wide corridors; they wove through denser crowds; they encountered structures as baffling and varied as the machinery - or artwork, or gardens - of the outpost in the Bright. The probes gathered information, and the toolkit puzzled over it, but even when it made sense it was just another tiny piece of a vast mosaic. Grabbing hints of how the vendek populations were interacting inside some gadget - or pet - that they passed was all grist for the mill, but it was not going to make the whole city and its people snap into focus in an instant.

Still, Tchicaya clung stubbornly to the notion that it was better to observe whatever he could, and provisionally entertain some wildly imperfect guesses, than to close his eyes and surrender to the verdict that he might as well have been a flea aspiring to understand the culture of a great metropolis. The scale in that analogy was right, but nothing else was. Both he and his hosts possessed general intelligence, and however mutually foreign their needs and drives, there was nothing - including each other"s lives, customs, and languages - that could remain incomprehensible to them, given time, patience, and motivation.

Time, they did not have, but he"d leave it to the Planck worms to declare when the supply was exhausted.

Mariama drank in the sights like a happily dazed tourist. She treated their purpose at least as seriously as he did, and she"d confronted every problem they"d faced with ferocious energy and clarity, but something in her temperament refused to admit that the corollary of that dedication could ever be despair at the thought of failure. They"d accepted a burden that was constantly on the verge of crushing them both, but he"d rarely seen her so much as tremble beneath the load.