There was no audio, so the roar of Grim Tim’s engine and the occasional whomps of displaced air, when vehicles passed them in either direction, became a soundtrack for the thing’s roadrunner trot through brush and rocks. It looked, she assumed, like the other three running with it, controlled, Conner said, by a swarming program. Like elongated tortoiseshells, mounted atop the hindquarters of miniature robot greyhounds, about a yard tall, assuming they could stand upright, something she hadn’t yet seen one do. They ran canted forward, which they’d done constantly since Conner had opened the feed, and were armless, their legs blurring when not confronted with an obstacle. "Where are they going?" she asked Conner.