Skade willed her gloves to clean themselves. The residue flowed back on to the wall. She thought of Clavain, wishing that she had some of his tolerance for sights like this. Clavain had seen horrid things during his time as a soldier, enough that he had developed the necessary mental armour to cope. With one or two exceptions, Skade had fought all her battles at a distance.
Her crest must have reflected her discomposure.
Felka floated in another chamber of her quiet residential spar. Where tools had been tethered to her waist earlier many small metal cages now orbited her, clacking gently against each other when she moved. Each cage contained a clutch of white mice, scratching and sniffing at their constraints. Felka paid them no attention; they had not been caged for long, they were well fed and shortly they would all enjoy a sort of freedom.
She squinted into gloom. The only source of light was the faint radiance of the adjacent room, separated from this one by a twisting throat of highly polished wood the colour of burned caramel. She found the UV lamp attached to one wall and flicked it on.
One side of the chamber — Felka had never bothered deciding which way was up — was sheeted over with bottle-green glass. Behind the glass was something that at first glance resembled a convoluted wooden plumbing system, a palimpsest of pipes and channels, gaskets and valves and pumps. Diagonals and doglegs of wood spanned the maze, bridging different regions, their function initially unclear. The pipes and channels had only three wooden sides, with the glass forming the fourth wall so that whatever flowed or scurried along them would be visible.
Felka had already introduced about a dozen mice to the system via one-way doors near the edge of the glass. They had quickly taken divergent paths at the first few junctions and were now metres apart, nosing through their own regions of the labyrinth. The lack of gravity did riot bother them at all; they could obtain enough traction against the wood to scamper freely in any direction. The more experienced mice, in fact, eventually learned the art of coasting down pipes, minimising the frictional area they exposed to the wood or glass. But they seldom learned that trick until they had been in the maze for several hours and through several reward cycles.
Felka reached for one of the cages attached to her waist, flipping open the catch so that the contents — three white mice — spilled into the maze. Away they went, momentarily gleeful to have escaped the metal prisons.
Felka waited. Sooner or later one of the mice would run into a trapdoor or flap that was connected to a delicate system of spring-loaded wooden levers. When the mouse pushed past the flap, the movement caused the levers to shift. The movement would often be transmitted across the maze, causing a shutter to open or close one or two metres away from the original trigger point. Another mouse, working its way through a remote stretch of the maze, might suddenly find its way blocked where previously it had been clear. Or the mouse might be forced to make a decision where previously none had been required, anxieties of possibility momentarily clouding its tiny rodent brain. It was quite probable that the choices of the second mouse would activate another trigger system, causing a distant reconfiguration of another part of the maze. Floating in the middle, Felka would watch it happen, the wood shifting through endless permutations, running a blind program whose agents were the mice themselves. It was fascinating enough to watch, after a fashion.
But Felka was easily bored. The maze, for her, was just the start of things. She would run the maze in semi- darkness, with the UV lamp burning. The mice had genes that expressed a set of proteins that caused them to fluoresce under ultraviolet illumination. She could see them clearly through the glass, moving smudges of bright purple. Felka watched them with ardent, but perceptibly waning, fascination.
The maze was entirely her invention. She had designed it and fashioned its wooden mechanisms herself. She had even tinkered with the mice to make them glow, though that had been the easy bit compared with all the fettling and filing that had been needed to get the traps and levers to work properly. For a while she even thought it had been worth it.
One of the few things that could still interest Felka was emergence. On Diadem, the first world they had visited after leaving Mars in the very first near-light ship, Clavain, Galiana and she had studied a vast crystalline organism which took years to express anything resembling a single ‘thought’. Its synaptic messengers were mindless black worms, burrowing through a shifting neural network of capillary ice channels threading an ageless glacier.
Clavain and Galiana had wrenched her away from the proper study of the Diadem glacier, and she had never quite forgiven them for it. Ever since, she had been drawn to similar systems, anything in which complexity emerged in an unpredictable fashion from simple elements. She had assembled countless simulations in software, but had never convinced herself that she was really capturing the essence of the problem. If complexity sprung from her systems — and it often had — she could never quite shake the sense that she had unwittingly built it in from the outset. The mice were a different approach. She had discarded the digital and embraced the analogue.
The first machine she had tried building had run on water. She had been inspired by details of a prototype that she had discovered in the Mother Nest’s cybernetics archive. Centuries earlier, long before the Transenlightenment, someone had made an analogue computer which was designed to model the flow of money within an economy. The machine was all glass retorts and valves and delicately balanced see-saws. Tinted fluids represented different market pressures and financial parameters: interest rates, inflation, trade deficits. The machine sloshed and gurgled, computing ferociously difficult integral equations by the power of applied fluid mechanics.
It had enchanted her. She had remade the prototype, adding a few sly refinements of her own. But though the machine had provided some amusement, she had seen only glimpses of emergent behaviour. The machine was too ruthlessly deterministic to throw up any genuine surprises.
Hence the mice. They were random agents, chaos on legs. She had concocted the new machine to exploit them, using their unpredictable scurrying to nudge it from state to state. The complex systems of levers and switches, trapdoors and junctions ensured that the maze was constantly mutating, squirming through phase- space — the mind-wrenching higher-dimensional mathematical space of all possible configurations that the maze could be in. There were attractors in that phase-space, like planets and stars dimpling a sheet of space-time. When the maze fell towards one of them it would often go into a kind of orbit, oscillating around one state until something, either a build-up of instability or an external kick, sent it careering elsewhere. Usually all that was needed was to tip a new mouse into the maze.
Occasionally, the maze would fall towards an attractor that caused the mice to be rewarded with more than the usual amount of food. She had been curious as to whether the mice — acting blindly, unable to knowingly co- operate with each other — would nonetheless find a way to steer the maze into the vicinity of one of those attractors. That, if it happened, would surely be a sign of emergence.
It had happened, once. But that batch of mice had never repeated the trick since. Felka had tipped more mice into the system, but they had only clogged up the maze, locking it near another attractor where nothing very interesting happened.
She had not completely given up on it. There were still subtleties of the maze that she did not fully understand, and until she did it would not begin to bore her. But at the back of her mind the fear was already there. She knew, beyond any doubt, that the maze could not fascinate her for very much longer.
The maze clicked and clunked, like a grandfather clock winding up to strike the hour. She heard the shutterlike clicking of doors opening and closing. The details of the maze were difficult to see behind the glass, but the flow of the mice betrayed its shifting geometry well enough.
‘Felka?’
A man forced his way through the connecting throat. He floated into the room, arresting his drift with a press of fingertips against polished wood. She could see his face faintly. His bald skull was not quite the right shape. It
