Bob is furry. Bob is green. Bob is white. Dave is cold. Dave is round. Dave is white. Harry is young. If someone is white and young then they are furry. All young people are round. White, green people are young. If someone is furry then they are round. All round people are cold. If someone is cold and white then they are blue. Cold people are green. If someone is green and round then they are young.
Harry is not blue.