"Hey, Len." Caraco, seated at the table with Brander, waves her over. "Check out the new look."

Brander's in real shirtsleeves. He doesn't even have his caps in.

His eyes are brown.

"Wow." Clarke doesn't know what else to say. Those eyes look really strange. She looks around, vaguely uncomfortable. Lubin's over on the sofa, watching. "What do you think, Ken?"

Lubin shakes his head. "Why do you want to look like a dryback?"

Brander shrugs. "Don't know. I just felt like giving my eyes a rest for a couple of hours. I guess seeing Scanlon down here in shirtsleeves all the time." Not that anyone would even think of popping their caps in front of Scanlon.

Caraco affects an exaggerated shudder. "Please. Tell me he's not your new role model."

"He wasn't even my old one," Brander says.

Clarke can't get used to it. "Doesn't it bother you?" —Walking around naked like that?

"Actually, the only thing that bothers me is I can't see squat. Unless someone wants to turn up the lights..."

"So anyway." Caraco picks up the thread of some previous conversation. "You came down here why?"

"It's safe," Brander says, blinking against his own personal darkness.

"Uh huh."

"Safer, anyway. You were up there not so long ago. Didn't you see it?"

"I think what I saw up there was sort of skewed. That's why I'm down here."

"You never thought that things were getting, well, top-heavy?"

Caraco shrugs. Clarke, imagining steamy needles of water, takes a step towards the corridor.

"I mean, look how fast the net changed," Brander says. "It wasn't that long ago you could just sit in your living room and go all over the world, remember? Anywhere could link up with anywhere else, for as long as they liked."

Clarke turns back. She remembers those days. Vaguely.

"What about the bugs?" she asks.

"There weren't any. Or there were, but they were really simple. Couldn't rewrite themselves, couldn't handle different operating systems. Just a minor inconvenience at first, really."

"But there were these laws they taught us in school," Caraco says.

Lenie remembers: "Explosive speciation. Brookes' Laws."

Brander holds up a finger. "Self-replicating information strings evolve as a sigmoid-difference function of replication error rate and generation time." Two fingers. "Evolving information strings are vulnerable to parasitism by competing strings with sigmoid-difference functions of lesser wavelength." Three. "Strings under pressure from parasites develop random substring-exchange protocols as a function of the wavelength ratio of the host and parasite sigmoid functions. Or something like that."

Caraco looks at Clarke, then back at Brander. "What?"

"Life evolves. Parasites evolve. Sex evolves to counter the parasites. Shuffles the genes so they have to shoot for a moving target. Everything else— species diversity, density-dependence, everything— it all follows from those three laws. You get a self-replicating string past a certain threshold, it's like a nuclear reaction."

"Life explodes," Clarke murmurs.