It’s the fat man’s fault. The stick men frantically rush to and fro with their plates of biscuits and in the middle squats the fat man, who doesn’t move, ever. He eats the biscuits and occasionally rewards the stick men with some crumbs, which makes them move even faster, which means he gets more biscuits.

As a demonstration of how altruism is generated by greed, it can’t be bettered. So I run the programme, write up the results, submit the paper to a scientific journal, and it’s published.

The visual output of the programme is crude; the men are nothing more than lines of black pixels moving around the screen. But I’ve managed to superimpose an image of my boss’s face onto the fat man.

That’s why my colleagues are laughing. My boss must have seen them gathered around my screen, and then run the simulation for himself, watching his own mouth gobbling virtual biscuit after biscuit.

‘I got a good paper out of this work, and it’s been cited by everyone, even Dawkins. I didn’t send the actual cartoon to the journal, I didn’t send it to anyone. No one was meant to see it, apart from me. It was just an accident that anyone else saw it.’

He comes over and stands far too close to me. I try to remember if I’ve ever seen him eat biscuits in real life.

But it’s not really about the biscuits at all. He sits in this office and makes us run around producing papers, conferences, and grants, and we have to bring everything in to be inspected and fed into his ego. The biscuits were just an analogy.

I look up at him, at the foreshortened view of his face with its features all bunched up by the unusual perspective. I feel an irritating twinge of pity. Up this close I can see that he’s human. I want to lean away.

‘I’m sorry,’ I say.

He smiles. Now I am really afraid.

‘Your time here is coming to an end soon,’ he reminds me. As if I need reminding. Like the prayer of a good catholic schoolgirl, it’s the last thing on my mind when I go to sleep and the first thing when I wake up. The vision of the end of the grant floats above me at all times. In this vision I am cast out of the lab by righteous angry angels and forced to take a job in some IT support hell.

‘Four months left,’ I say. Still time to get a new grant. There’s a silence in which we stare at each other. Fortunately, he moves away.

‘It may be better if you go elsewhere,’ he says finally.

‘Better?’

He nods, ‘You’ve done some – ’ and here he pauses for a long time, ‘interesting work, but you’ve been here for some time. A lab like this thrives on new blood.’

Back in my office the fury surfaces. I thump the desk with my fist, hard enough to make the keyboard clatter.

With the fury comes the idea. It crashes into my mind and once it’s there it won’t leave. My neurons love it. They buzz around it, feeding it, and helping it grow, until it firmly takes root and demands action. If he’s going to get revenge on me because of something I’ve done in some virtual reality and ‘let me go’, then I will retaliate. In real space.

I have to break into the lab to do it. If you were being dramatic, you’d imagine broken glass on the floor, and a figure prowling around the dim space with a stocking over her head.

But it’s more mundane than that. A small matter of taking one of the technicians to the pub and a few drinks too many. For him, not for me; I have work to do. Then it’s easy to engineer a drunken fumble in the car park, during which I’m able to steal his swipe-card from his trouser pocket. After I’ve sent him packing in a taxi, I come back to the lab.

It feels odd at first because I don’t often come down here. My domain is upstairs in the realm of virtual existence, where births, deaths and everything in between are played out with numbers and pixels. Down here even the smell, both sharp and dank at the same time, feels three-dimensional. In the corner a dripping tap sounds like a heartbeat. A row of ghost-white coats hanging on the wall watch me.

But I’m able to ignore the coats; I know what I’m doing here. I’ve watched the technicians at work. I go over to the incubators where the samples are kept and open one of the doors. A neat stack of flasks glints in the streetlight. I scrape my cheek with a wooden spatula, and rinse what I’ve collected. I like the idea of my cells becoming decontaminated, and pure. At this stage the cells are practically invisible and I can barely see them as I deposit them in a flask. I hold the flask up to the window, imagining them growing, forming a thin film on the culture, becoming more substantial, and making their presence felt. I smile, before returning the flask to the incubator.

I want to work my way through all the flasks, but there are over a thousand of them and my cheeks become raw very quickly, so I decide to use other orifices. There’s a full moon shining down on me as I squat on the laboratory floor and reach up inside myself to get at my innermost cells. When I’ve finished with all the experiments, I feel a great sense of satisfaction. As I turn to leave the laboratory that final time and take one last glance inside the nearest incubator, I notice that the complicated geometrical shapes of the flasks make them look like rows of tiny coffins.

In between completing job applications, I carry on developing my new computer programme. Now, I set it running yet again and watch the screen. After a few minutes a patch of virtual cells appear, all identical at first, and then they start to differentiate so that some stay round and become transparent, and others elongate into thin lines or shrink into dots. Gradually an overall shape emerges, and in ten minutes there’s an eye staring back at me.

When I first ran this code, it unsettled me. Even now, the eye brings me up sharp. It looks at me coldly, as if to say, ‘Well? So what?’

‘Give me a break,’ I reply, ‘Go on, work for once.’

But it just carries on staring, never blinking. I make a note that something is still not quite right in the code. It needs to blink, otherwise it will start to get clogged up with unshed tears. I wait a bit and sure enough, the eye clouds over and goes blind.

I settle back into my routines as I wait for the results of the job applications. I go to the pub with my colleagues. I write more code. I get my hair cut. The technician compliments me on it and asks me out for another drink. I go, and this time we share a bottle of wine. The next morning I wake up in a strange bed, and the weight of the technician’s arm lying across my body stops me from leaving.

My new code still isn’t working very well. The technician is worried, too. We go out for dinner and he tells me something’s happened to the experiments in the lab.

‘These new cells are a funny shape too,’ he says, ‘I’ve never seen cells like them before. We’re wondering if someone opened a window at a crucial stage and things got contaminated.’

I smile at my plate. It’s nice to have such an impact on your surroundings.

Later on, as he’s shedding some of his cells inside me, I run a finger around the swirls of one of his ears, and I examine the colours of his eyelashes. I realise there’s no end to the complexities of his body. It’ll take me a long time to learn it all.

Usually, as he runs upstairs to meet me after work, he’s whistling. Today there’s just silence.

‘Not happy to see me?’ I say.

‘Of course,’ he replies, ‘But I’ve had a difficult day.’

I try to persuade him to come to my flat, but he doesn’t seem keen. He wants to go back to work, and figure out what’s happening there. We sit in my car and I see that some of his fingers are twitching slightly. It’s raining outside and the water washes down the car windows.

‘The new cells won’t stop developing,’ he says, not facing me.

‘Won’t stop?’ I echo him.

‘They’re multiplying out of control, and nothing seems to kill them off. They’re not like normal cells. They’re immortal.’

I realise I’m hunched over, as if I have a pain inside me. Perhaps I do have a pain. Nothing seems certain any more. I stroke the inside of my mouth with my tongue. It might have been something else. It might be nothing to do with me.

‘I’m sorry,’ he says, ‘I don’t have time to talk.’ He gets out of the car, and after a few seconds he’s disappeared into the rain.

I sit in the car for a bit longer, still hunched over, before I go back as well. There’s nothing else to do but work. When I sit down in front of my computer I run the code yet again. All of a sudden the eye appears, fully formed. It stares at me.

It still won’t blink, but neither does it cloud over. It just looks. It seems to see right into me, through my skin and muscle, into my organs and bones. I feel stripped and flayed, like a dissected body.

The eye sees all. I try and stare back at it, but I have to look away. It knows what I’ve done and now I must pay the price. I reach out to phone the doctor.