What then of virtuality? Would the realities be no longer contiguous, but intersecting?
'Hey, lady!'
She continued walking away from him.
'Lady!' The young man had left his pitch in the doorway, and he laid a hand on her arm.
She snatched it away from him.
'Quit that!' she said loudly. 'I'm not interested!'
'You lady, you one of us? You Shandy?'
His tone was no longer flat and automated, the voice of the shill. An earnestness gripped him.
He was pointing at her neck. Teresa saw how young he was, hardly more than in his middle teens. He turned his head away, and laid a finger against the base of his own neck.
There was a nanochip valve embedded there. it was obvious what it was, but it was unlike any other Teresa had
seen. it was larger than hers, and was made of bright purple plastic: lt was set in a mount made of some silvery material, probably plastic again but glossed up brilliantly. The valve looked like a cheap stone in a gaudy setting.
Teresa had always been selfconscious about her ernbedded valve, thinking that to anyone who didn't know what it was it must look like something left over from an operation. She usually wore a high collar or scarf in an attempt to conceal it. By contrast, the youth's nanochip valve was almost flagrantly exposed, a startling flash of colour on the back of his neck, like bodypiercing, a fashion statement, a tribal declaration.
'You know ExEx, lady? You real thing! Big, big discount for real ExEx! We find you Shandy, you bet!'
'No,' she said yet again, but less assertively than before. 'Look, 1 know what ExEx is. 1 was just surprised to find it. Open to the public.'
'Members only. You join! You no come in? Special deal before evenings.'
Realizing she was wasting her time, and had been doing so from the first exchange of words, Teresa backed away. The youth tried again to lure her inside, but she turned her back on him and strode off in what she hoped looked like a determined way. She soon reached the junction with Shaftesbury Avenue, and had to wait for a break in the traffic before she could cross. She glanced back: there was no sign of the young man.
She walked to Charing Cross Road, and spent nearly an hour trying to distract herself in one of the big bookstores; after this she returned to the Leicester Square area and went i see a movie. She caught the last train back to Bulverton with minutes to spare; she had not looked at the timetable In advance, and discovered she was lucky to have caught it.
An hour later, as the train left Tunbdidge Wells and moved into the almost unbroken darkness of the Sussex countryside, Teresa, alone in the carriage, closed her eyes and tried to doze. She was bodytired from all the walking she had done in London, but stimulated and alive mentally.
She had barely been able to keep her mind on the film, in spite of the intrusively loud music and explosive special effects. Something had unexpectedly become clear to her. At the beginning of the show, as she sat in the auditorium waiting for the lights to go down, she had remembered the conversation in the hotel corridor with Ken Mitchell, and the seemingly impenetrable objections he had raised to her presence in the hotel.
His talk of linear coherence and iterative purity had sounded at the time like codebabble to her, the natural language of the computer geek. But the Shandy scenario had undermined everything. That thought she had had, outside the ExEx dive, about the way reality might be made to intersect, made her think she understood at last what Mitchell had been driving at.
An ExEx scenario already represented a sort of intersection. lt stood at the interface between human variables and digital logic.
The programmers took people's memories of certain events, their feelings about the events, the stones they told about them afterwards, the imagination surrounding them, and even their guesses at what the events had actually been, they took all of these and coded them into a form of objectified experience, and made them seem real, or virtually so. Thus were the scenarios derived.
Mitchell had spoken of what he called reactional crossover: the fact that the ExEx user will inadvertently affect the shape of the scenario, so that on second and subsequent visits the scenario will seem to have modified itself to take
account of the previous visit or visits.
From the start she had been all too aware of the interactive nature of ExEx. The only difference since then was her growing understanding of how interactivity was a way of testing the limits of the scenarios.
Why she should be a perceived threat to the programmers was a mystery to her.
But that wild thought of the afternoon: entering Shandy's scenario, moving around within it, testing its extremities, going with ExEx Shandy to the ExEx dive off Shaftesbury Avenue, then entering another ExEx scenario, a simulation within a simulation ...
it couldn't happen then. Then was 1990, before ExEx had been made publicly available, probably before it had even been developed. The simulation of London that was Shandy's home would not include the ExEx dive.
Things had changed since 1990. Sitting in the cinema, as the film began, Teresa had recalled the logical problems that Gerry Grove presented. The guns, and the unexplained passage of time during his final afternoon of life.
lt was known that Grove had been to the Bulverton ExEx building between his first murders, the killing of the mother and her child picnicking in the woods near Ninfield, and his final explosive spree. lt was not known what he had done while he was in there.
When she had asked the staff in the building about this, expecting them to remember, they were vague and
