“And let me point out,” Ira pursued, eager to clinch the sale, “that the Model I is so life-like that, in normal operation, it is almost completely silent. Only a faint throbbing—like that of a human heart—is noticeable.”

The woman cocked her head to a side. “I don’t hear anything,” she said.

Ira smiled triumphantly. “Of course, you don’t! Come here,” he said. “Put your ear to my chest and you’ll just be able to make it out.”