to find the region abandoned, given the absence of machinery on the other side of the link.
The beacon seemed to dim with unnatural speed, as if the polis was accelerating away wildly. Yet another manifestation of the inverse-fourth law: anything that spread out in all directions thinned more rapidly here. Orlando watched the reassuring pulse of light fade from view, then managed to laugh at his visceral sense of abandonment. It was possible to be stranded anywhere. On Earth, he'd once almost died of exposure less than twenty kilometers from home. Scale meant nothing. Distance meant nothing. They'd either make it back, or they wouldn't and nothing this world could do to them could begin to compare to a slow death from cold and dehydration.
He addressed the scape. 'Sweep the sky.' At any one moment, the ordinary view from the Island—a mere two-dimensional dome—could only encompass a narrow portion of the macrosphere's four-dimensional sky. But the hemisphere could he swept across the sky, scanning it like a Flatlander scanning ordinary space by rotating the plane of vis slit-like view. Orlando watched the sparse stars come and go, far fewer than he'd have seen from Atlanta beneath a full moon. Still, it was remarkable that he could make out so many, when they were scattered so widely and their light was spread so thin.
A brilliant rust-red point of light appeared in the east, then faded rapidly as the view swept over it: Poincare, the nearest star to the singularity, their first target for exploration. It would take forty megatau to reach Poincare, but no one was tempted to freeze themselves for the journey; there was too much to think about, too much to do. Orlando braced himself. 'Now show me U-star.' His exoself responded to the command, spinning his balls into hyperspheres, rebuilding his retinas as four-dimensional arrays, rewiring his visual cortex, boosting his neural model of the space around him to encompass five dimensions. As the world inside his head expanded, he cried out and closed his eyes, panic-stricken and vertiginous. He'd done this in sixteen dimensions to view the Orphean squid, but that had been a game, a dizzying novelty, like riding a comet or swimming with blood cells, adrenaline- pumping but inconsequential. The macrosphere was no game; it was more real than the Floating Island, more real than his simulated flesh, more real, here and now, than the ruins of Atlanta buried in a distant speck of vacuum. It was the space through which the polis sped, the arena in which everything he thought and felt was truly happening.
He opened his eyes.
He could see many more stars at once now, but they seemed more sparsely distributed; there was so much more emptiness to fill. Almost without thinking, he began joining up the dots, sketching simple constellations in his head. There were no striking figures here, no Scorpios or Orions, but a single line between two stars was a thing to be marveled at. His vision now stretched beyond its ordinary field in two orthogonal directions; Paolo's friend Karpal had suggested calling them quadral and quintal, but with no obvious basis for distinguishing between them Orlando seized on the collective term: the hyperal plane.
Networks in his new visual cortex and spatial map attached a raw perceptual distinction to the hyperal directions, but it still required a conscious effort to make cognitive sense of them. They were definitely not vertical; that realization carried the most immediate force. The direction of gravity, of his body's major axis, had nothing to do with them; if he was like a Flatlander seeing the world beyond his plane, that plane had always been vertical, and his slit-vision had now spread sideways. But the new directions weren't lateral, either; unlike a vertical Flatlander, his 'sideways' was already occupied. When he consciously divided his visual field into left and right halves, all the purely hyperal pairs of stars lay solely in one half or the other, just like all the purely vertical pairs. And whatever common sense dictated as the only remaining possibility, there was no sense of the sky having gained depth, of the stars looming toward him like a holographic image leaping out of a screen.
Orlando held these three negations in his mind at once. The hyperal plane was clearly defined by his anatomy, so long as he remembered that it was perpendicular to all three of his body's axes.
One vaguely cruciform constellation lay almost flat in the hyperal plane: every one of the four stars shared roughly the same altitude above the horizon, and the same left-right azimuthal bearing, and yet they were not bunched together in the sky; the hyperal directions kept them as far apart as the stars of the Southern Cross. Orlando struggled to attach labels to them: sinister and dexter for the quadral pair, gauche and droit for the quintal. It was completely arbitrary, though, like assigning compass points to a fictitious map drawn on a circular piece of paper.
Several degrees away to the left-up-dexter-gauche he could see another four stars; these lay in the lateral plane, the plane of the 'ordinary' sky. Mentally extending the two planes and visualizing their intersection was a very peculiar experience. They met in a single point. Planes were supposed to intersect along lines, but these ones refused to oblige. A quadral line running between the sinister and dexter stars of the Hyperal Cross pierced the vertical plane at right angles to both arms of the Vertical Cross… but so did the quintal line. There were four lines in the sky—or in his head—that were all mutually perpendicular.
And the sky still looked flat.
Nervously, Orlando let his gaze drop. Stars were visible below the horizon—not through the ground, but around it, as if he was standing on a narrow, jutting cliff, or a sharp pillar. He'd chosen to have no power to twist his head or body out of the usual three dimensions of the scape, though his eyes bulged literally out of his skull, hyperally, to capture a broad swath of extra information. He pictured a vertical Flatlander with two eye-circles, one above the other, suddenly made spherical, their axes still confined to swivel within the planar world but their lenses, their pupils, their field of view, protruding beyond it. As well as being a ludicrous anatomical impossibility, this compromise was now beginning to induce a giddy mixture of vertigo and claustrophobia. The Island had negligible width in the extra dimensions, and he could see clearly that the slightest hyperal movement of his body would send him plummeting into space like a drunken cosmic stylite. At the same time, the physical confinement that prevented this made him feel like he was wedged between two sheets of glass, or afflicted by some bizarre neurological disease that robbed him of the ability to move in certain directions.
'Restore me.'
His visual field collapsed to a relative pinhole, and for a moment he felt so infuriatingly diminished that he shook his head wildly, trying to cast off the blinkers. Then abruptly his vision seemed gloriously normal, and the macrosphere's wide sky was like a fading memory of a disorienting optical illusion.
He wiped the sweat from his eyes. It was a start. A small taste of reality. Maybe he'd work up the courage eventually to wander a fully five-dimensional scape wearing a five-dimensional anatomy. Apart from the alarming possibility of glancing down and catching a glimpse of his own internal organs—like a Flatlander who twisted vis head out of the plane—unless he added two dimensions to his simulated flesh—he'd have the balancing skills of a paper doll, once he was free to fall quadrally and quintally.
But even gaining the anatomy and instincts to navigate five dimensions would only be scratching the surface. There'd always be more to adapt. In the flesh, he'd been scuba-diving dozens of times, but he'd barely been able to communicate with amphibious exuberants. The Transmuters had been here for at least a billion years or a roughly comparable period of macrosphere time, in terms of the rates of the most likely biochemical or cybernetic processes. Of course, they were sentient creatures in control of their own destiny, not beached fish required to have the right mutations in order to survive. They might not have changed at all. They might have clung like good realists—or good abstractionists—to simulations of the old world.
But over the eons, they might easily have decided to acclimatize to their new surroundings. And if they had, communication could prove impossible, unless someone, in the expedition was prepared to meet them halfway. Unless someone was prepared to bridge the gap.
The Flight Deck was crowded, making it a perfect environment in which to practice negotiating unpredictable obstacles, but Orlando found himself spending most of his time transfixed by the view. One entire wall of the penteractal scape was given over to a giant window, and the magnified image of Poincare behind it offered a perfect excuse to do nothing but stand and stare. Moving about in public 5-scapes still made Orlando intensely self-conscious, less out of any fear of falling flat on his face than from a strong sense that he could take no credit for the fact that he didn't. His 5-body came equipped with numerous invaluable reflexes, as any real macrospherean body almost certainly would, but relying on these alien instincts made him feel like he was operating a telepresence robot programmed with so many autonomous responses that any instructions he gave it would be superfluous.
He glanced down at the bottom of the window. The most trivial details in a 5-scape could still be hypnotic; the tesseract of the window met the tesseract of the floor along, not a line, but a roughly cubical volume. That he
