‘And you guys,’ she said to Bob and Becks. ‘Split up … I don’t want you two support units Bluetoothing binary jibber-jabber to each other all morning. You should use this morning to do some more people-watching. Look and listen … watch how people talk and move and stuff.’ She glanced up at Bob. ‘Particularly you, Bob … you still come across as a bit stiff and unnatural. You need to learn how to chillax.’

Maddy watched Bob’s seven-foot frame hunch uncertainly. His thick brow arched and his mouth opened.

Beauty and the Beast. He was seven foot tall, three hundred pounds of muscle and bone: a panzer tank in human form. Becks by contrast was half a yard shorter, athletic and slight. Yet both had started out, once upon a time, as identical-looking foetuses growing in a tube of murky gunk.

Bob was cocking his head like a dog, puzzling over the term ‘chillax’.

‘Never mind.’ Maddy shook her head. ‘Just mingle a bit, OK?’

Both support units nodded sternly.

‘Right,’ said Maddy, honking into a hankie. ‘Right then, meet in the cafe up on the first floor in, say … like, two hours?’ She tried a weary flu-ridden smile. ‘And hey … you know, have fun everyone.’

Maddy watched them disperse: Liam drawn towards the entrance of the natural-history hall and the dinosaur dioramas; Sal hovering a moment, undecided, before choosing to go to the History of Native Americans exhibit on the third floor; and Bob and Becks looking for a moment like abandoned children before picking directions at random in which to saunter away.

She watched both go with the oddest feeling of motherly instinct for the pair of them. Bob still moved around with a machine-like gait and stony-faced concentration that made him look like a Neanderthal with an anger-management problem. While Becks moved with ballerina grace; equally lethal as a killing machine in an understated way.

Weird. How different they both were: their bodies drawn from the same genetic material, their minds both running the same AI operating system, and yet their experiences, their memories, were varied enough to evolve two very different simulated intelligences. It was a bit like being a parent, Maddy supposed, watching both support units slowly ‘grow up’ and become different personalities over time.