Why did this picture speak to me? Well, without the suitcase to provide an excuse for her twirling, the Lady in Blue is just spinning for the sake of spinning. She's taking solitary pleasure in the sensation of motion, the feel of her skirts swirling around her, and of her hair streaming out behind her head. She's in her own world, completely absorbed in what her senses are telling her.
She is stimming, in other words.