Situation: I am using some help from the stool to reach some book on the shelf.
Alternative situations: I am standing on a stool to reach the highest part of the the bookshelf in front of me. I am standing on the stool putting a book back on a higher shelf. I am standing on a stool to reach the highest shelf on the bookshelf in front of me to get a book.
Question: What is against the wall to my left?