The book "A Pocketful of Posies" by Beatrix Potter does not feature a sofa, nor does it mention any objects on a sofa. The book tells the story of a little girl named Jemima Puddle-Duck who is gifted a bunch of flowers by her mother, and it's primarily focused on Jemima's adventures with these flowers.
Perhaps you are thinking of a different book by Beatrix Potter? If you can provide more details about the book you are referring to, I might be able to help you further.