“The real kicker has been that, because they’ve come to believe that humanity represents the highest standards, genuine humans are found wanting by them. Derec, your mother couldn’t have foreseen such a tantalizing irony. When she finds out, she’ll be quite thrilled.

“See, if another kind of being were to enter the city tomorrow, and it was a shade smarter than us, as those blackbodies you told me about might have been, then they would be convinced the newcomers are the humans, and it’s goodbye, Derec, Ariel, Avery. It wouldn’t matter if the newcomers were covered with slime, smelled like erupting sewers, and killed each other for fingernail scrapings.

“Anthropologically speaking, the key information that’s been denied them by not being programmed with detailed knowledge of humans is the data which would inform them of the nature of our culture. Another aspect of the denial process would appear to be the absence in their knowledge of our unfortunate tendencies toward emotion. They can’t understand that culture and emotion define humanity as much as intelligence does.

“Since they don’t know what a human really is, they have the freedom to enter an alien culture and adopt its ways easily. Once they believe that culture is human, then all its customs, rites, behavior patterns become logical. What a fruitful arena for anthropological study this’d make. I mean, do you see, Derec?”

When Avery stopped pacing, Derec halted a short beat later. They faced each other. Wolruf found an excitement in the way the two of them were now so furiously working together. For the first time she realized they must be father and son.

“You’re saying that the Silversides and our mystery robot could be catalysts for, say, a study of what happens to cultures when they encounter robots like the Silversides?” Derec asked.

“Exactly. And also what happens to them when they are introduced to cultures. I think that’s where the shape-changing ability comes in. Once they join a culture, they become like the individuals in it. They are assimilated, a word dear to social scientists everywhere. Then these robots, sent to discover a culture, become integrated into it. They can become the leader, as Adam did with the kin. Or they can be corrupted by the culture itself, as both Adam and Eve were with the blackbodies. Or they can even disrupt its environment. We and the robots are the ‘culture’ here in Robot City, and our Pinch Me has been studying us, manipulating us.

“You know what the real clue is? The dancers and all the other little creatures. I suspect they’re some sort of genetic/robotic experiments Pinch Me has been conducting. They are, in a way, its own tiny anthropological studies.

“Without humans, or any kind of being other than robots, to examine, it started to create its own subjects, restricted cultures that it could study anthropologically. They failed for the most part, I think. At least it seemed to get bored with them and store them away in buildings allover the city. But somehow they are based on its acquired knowledge of humanity, knowledge derived no doubt from the computer.

“The trouble is, Pinch Me doesn’t know how to deal with applied knowledge, so he combined some robotics data with some genetic experimental information and created the dancers and the other groups. That he could do as well as he did is impressive, but he couldn’t quite get the hang of it all. So his experiments were failures, he couldn’t control the city, and he even messed up his foray among us in disguise.”

Derec nodded. “That’s all highly speculative, but it does provide some ideas that fit the facts we do know.”

Avery paced a few steps more, then said, “It’s your mother’s failure really. She’s conceived this intricate anthropological study, probably to study positronic minds in various cultural situations. Like our Pinch Me, her work is theoretical, almost playful. Just the way she was.”

Even though he felt a twinge of irritation at the mere suggestion that his mother could have botched her experiment, Derec seemed to be gradually getting a picture of her through Avery’s asides. He figured if he could keep his father talking, he’d find out a great deal about her, especially when Avery was in a bitter mood and not guarding his words.

“She never was practical in her work. I suppose that was another standoff in our marriage. She could go off on such flights of fancy that I couldn’t bring her back to ground.”

“I wish I could meet her.”

Derec’s words angered Avery.

“I can see what you’re thinking. If she’s behind these robots, then maybe she’ll be around to check on them. Well, forget that. She has to leave them alone, let things happen long enough for data to be collected. So she won’t be showing up to see how her little creations have evolved for some time, years maybe. Keeping a watch on the Silversides won’t bring about any reunions for you, Derec.”

Derec kept his anger in check. There was no point in irritating his father any further. Give him some time, and maybe he’d relent on the subject of Derec’s mother, although he did seem adamant in his hatred of her.

“I’ll keep all that in mind,” Derec said. “For now, we have to find this third robot. I hope Mandelbrot and Timestep haven’t lost him.”

“Now that we have a concept of what we’re looking for, we can-”

Avery was interrupted by the appearance of Ariel in the doorway. She was out of breath from running.

“Derec! Dr. Avery! Something’s happening outside. Buildings are, I don’t know how to describe it, they’re self-destructing or something. Folding inward, sliding into the ground, falling over, disappearing altogether. Come see.”

Derec began to run out of the room immediately, Avery close behind. Ariel led them out to the street just in time to see a structure down the block begin to tremble, then-without a sound-fall sideways against another building, which in turn fell forward.

“There’s an ancient game, dominoes,” Avery remarked. “Sometimes people lined them up and they fell, toppling each other, something like those buildings there.”

“What’s doing this?” Ariel yelled.

“I should have known,” Derec said and begun running down the street. “Our robot,” he yelled back to Avery, “he’s trying to destroy everything. He has to be at the central computer.”

“I think you’re right,” Avery said, and ran after Derec.

“What robot?” Ariel said before taking up her position as third in line.

Wolruf limped out of the doorway and watched the trio disappear around a corner.

In the distance there was a bright flash of light and a tall narrow building’s sides began to undulate before the whole structure seemed to collapse inward.

“No way to get any resst arround here,” she said and loped after them. As the pain worked its way out of her leg, she picked up speed.