 Why does Grannie fool Billy as well when she rides away with Park?
DOUBLE TROUBLE by CARL JACOBI Grannie Annie, that waspish science-fiction writer, was in a jam again. What with red-spot fever, talking cockatoos and flagpole trees, I was running in circles—especially since Grannie became twins every now and then. Grannie Annie strode in the lead, her absurd long-skirted black dress looking as out of place in this desert as the trees. If my calculations are right, we've hit it at its narrowest spot." He could be excused this time, however, for this was only our third day on Jupiter's Eighth Moon, and the country was still strange to us. But Miss Flowers, known to her friends as Grannie Annie, had always been mildly crazy. If you haven't read her books, you've missed something. Blood-and-thunder as these books are, however, they have one redeeming feature—authenticity of background. Grannie Annie was the original research digger-upper, and when she laid the setting of a yarn on a star of the sixth magnitude, only a transportation-velocity of less than light could prevent her from visiting her "stage" in person. He was an old prospector Grannie had met, and he had become so attached to the authoress he now followed her wherever she went. As for Xartal, he was a Martian and was slated to do the illustrations for Grannie's new book. And then I was shaking hands with Antlers Park, the manager of I. V. himself. Antlers Park flicked the ash from his cheroot and shrugged. So now here we were at the outer reaches of the Baldric, four travelers on foot with only the barest necessities in the way of equipment and supplies. Xartal, the Martian illustrator, already had a notebook in his hands and was sketching a likeness of the creature. And then all at once Grannie stopped again, this time at the top of a high ridge. "Billy-boy," she said to me in a strange voice, "look down there and tell me what you see." As that dot continued to move across the heavens in a single direction, I called Grannie's attention to it. Attached to its hood was a taut wire which slanted up into the sky to connect with the kite. Five minutes later Grannie was shaking his hand vigorously and mumbling introductions. Occasionally he touched a stud on an electric windlass to which the kite wire was attached. Apparently these adjustments moved planes or fins on the kite and accounted for the car's ability to move in any direction.
 She didn't. It was one of the cockatoo images.
 She didn't want Billy to know where they were heading.  She had to pretend she was replaced by a cockatoo, and make it convincing.  She didn't want Antler to know about the cockatoo images and how they worked.  She didn't. It was one of the cockatoo images.