Dave is blue. Dave is furry. Dave is not red. Dave is rough. Dave is round. Dave is smart. Dave is young. Gary is furry. Gary is rough. Gary is not smart. Gary is young. Harry is furry. Harry is red. Harry is rough. Harry is smart. Harry is young. If something is not round then it is young. If Gary is young and Gary is not red then Gary is not blue. If something is blue and not rough then it is furry. If something is blue and not rough then it is smart. If Harry is blue and Harry is not round then Harry is furry. If something is rough and not blue then it is furry.
Gary is not blue.