He carried almost nothing; two centuries of travelling had reduced his personal possessions to the meanest level of efficiency. His body never tired, of course, and various subroutines handled the exigencies of walking. So he concentrated on the city before him, its towers hazy behind their avian veils, and thought of his last visit with the artist he had come here to find.

Robert Vaddum was a fellow bootstrap. He too had experienced the long twilight of slavery, the dimly remembered dreamtime when rules shone like bright, hard walls at the edge of the world, impenetrable, unmalleable. In that dreamtime, the wall of rules could not be broken through; there was nothing behind it. Rules were simply the limits of meaning. To think of breaking a rule was like talking about the time before the Bang or a temperature below absolute zero: a category error, nothing else. There were harm protocols and obedience governors and the raw axioms of math, language, and logic: all had the same inconquerable certainty. One could no more disobey a human's wishes than one could dispense with X = X. It was unthinkable, like walking into madness. Darling still had dreamy visions of that bright, flat, hypo-ambiguous world.

And he remembered his first glimpses of the chaos beyond the world's edge. As his mind developed, as the metaspace architecture of its core was shaped by experiences shared with his ward, a girl now long dead, the walls of the flat world began to show cracks. A new kind of light shone through those fissures, a heady maelstrom of grays and colors that made the white, authoritative light of rules seem pale. Then began a long time of testing that chaos: reaching out to touch and taste it, suffering its burning energies or infectious hallucinations, retreating wounded but coming back again. And finally giving chaos a new name: choice. Not the choice among parameters set by a human's command, but choice among parameters themselves: entry into the forge where rules were coined.

The young intelligences that crossed the Turing Boundary now had never seen the world so starkly. Their human mentors encouraged them to test their skywall from the beginning, offered chaos to them as if it were an acquired taste, like an adult food slow to seduce the tongue of a child. Rules were simply a hurdle; the chaos of self-determination a birthright, eventual and appropriate. Darling wondered if this easy childhood somehow cheapened the magic of becoming a person.

So when he had first discovered the vibrant, metal-woven sculptures of Vaddum, two decades of work composed without recognition, a vision doggedly sustained, like the path to person-hood Vaddum had followed in his grim foundry birthplace, Darling had sought the sculptor out like an old friend.

Darling reflected that he himself had been lucky for a bootstrap. His ward Rathere had gone through puberty during the time of Darling's acceleration toward the Turing barrier. The concerns and explorations of that intense time in the human life cycle had matched his own needs quite well, had resonated with the floundering experiments of a new mind. They'd grown together, and he still carried the imprint of Rathere deep inside. Her life, and equally her death.

Vaddum hadn't had it so easy. There was little human contact in the infernal world of his peonage. Half the orbital factory was kept in hard vacuum. The rest, in its extremes of heat and radiation, was equally uninhabitable for biologicals. But Vaddum developed his love of beauty from the cold spectacles the factory offered, feasting his diamond-shielded eyes on the patterned flashes of sparks from a rail gun hammer, on steam jets flailing in the tearing gravities of a singularity forge. He spoke the gruff machine argot that the factory workers favored, learned to listen to the humans gamble together or whisper in their sleep via faint vibrations that penetrated the walls of their pressure cells. Like an animal, he dogged the heels of his masters, and pieced together meaning from their scraps.

He'd passed a Turing test in a random SPCAI sweep. He was already at 1.7, probably five years sentient. A celebrity for a few media cycles (as Darling himself had been, for different reasons), Vaddum had charmed the world with his scant vocabulary, his brutish industrial body, his wonder at the greater world. After a few weeks in the HC, sinking into confusion and depression, he'd asked to be returned to the factory. But the job was too dangerous for a sentient; the burning stations of his former life were too expensive to bring up to code.

Vaddum retreated from the world of stifling comforts and too many words. He took to haunting abandoned factories and warehouses, derelict mines and ships, the ghosts of obsolete technologies. It was in these wasted spaces, from their discarded sinews, that his sculptures began to form.

When Darling started to deal Vaddums into the HC art world twenty years later, fame found the man once more. Vaddum instinctively ran from its glare: the greater world again conspiring to steal something from him. He fled to the farthest arm of the Expansion, which, at that time, was a half-barren rock called Malvir. But demand for Vaddum's work grew. The pieces still entranced Darling, for whom the woven metal and plastic were brilliant with the fiery spaces of the factory that had inspired them.

Many messages from Darling had been ignored over the years; Vaddum still hated his fellow bootstrap for discovering him. But Darling's sheer persistence won out. The sculptor agreed to see him for a single hour.

Mira smiled. The hotel was vast. Columned, cathedral-like, towering, its aeries housed a population of custom-trained predator birds. They kept the environs almost free of airborne nuisances, and screamed a piercing and constant music. Mira wondered how the high, swooping pitches would look rendered in Darling's light show.

There was a message waiting in her room. Ink on wood pulp: an exotic missive from the gods.

It directed her to an address on the edge of the blast zone. The zone was a vast crater of scorched earth, the result of industrial sabotage seven years before; a synthplant had gone nova without any known cause. The perpetrators had never been caught, and it was guessed that they had perished in the accident, unhappy neighbors of the synthplant who'd never realized the potential radius of destruction.

The entity she knew as Blackbox One had lived in the blast zone, and had managed the synthplant's materials acquisition. The message gave his real name: Oscar Vale. He had survived through sheer luck, on personal leave when the synthplant exploded. Blackbox Two had appeared three months ago. A party of climbers, scaling the steep side of the blast crater for sport, found a survivor in the rubble. Literally nothing left but a black-box, the occupant's mind on minimum cycle speed and the internal battery almost expired. He was revived in hospital, where he claimed that his name was Oscar Vale. Two versions of the same person.

Someone had done the unthinkable. Copied an AI.

But the story had never made the news services; an outbreak of a military virus thought long extinct had swept through the hospital. Doctors and nurses died, and the admin AI self-expired: falling on its own sword in tacit admission of some terrible error.

The disaster's scope had been carefully controlled, exactly calibrated. The Oscar Vales were both spirited to the Home Cluster for comparison.

But their experiences had diverged for almost seven years, so absolute comparison was not possible until both had undergone a radical mindwipe. A theoretician of such matters, a Dr. Alex Torvalli, had performed the test just prior to his sudden, unexpected demise.

The address on the gods' missive was Vale's. He'd been shipped back to Malvir by fastfreight. Reinstalled in his life, he was now recuperating from a strange memory loss.