A glitch turns the city green for an afternoon, and the (green) Lord Mayor powers up the ancient patchwork of public address. “Full chromatics will be restored soon,” crackle the bullhorns and gramophones. “We anticipate no reboot.”

The morning does show improvement: dark things are yellow, light things blue. “Recompiling,” says the Lord Mayor, “better soon!” By five o’clock Spaks and his shop friends have a homebrew fix. They try it at an intersection. The police arrive quite soon.

“I personally don’t mind,” says the arresting sergeant, “but it’s a matter of principle,” and Spaks’s mouth sprays gold on the wall.