Ah. The spaceship Serenity. That would explain why the 'shuttle' didn't quite look like the shuttle Leto had first seen with Wash. "Of course," Leto said. And then, "I would love a picture."
He watched the marks on the paper as she drew. And as she drew, he wondered just what exactly was going through her head. But the further she got into the drawing, the more Leto's thoughts slipped.
It was impossible, of course, but it looked as if this little girl had drawn Arrakis -- and the great sandworms within the dunes.
"What are you drawing?" he asked at last, before she'd quite completed it.