Bob is rough. Bob is round. Bob is smart. Bob is white. Dave is green. Dave is round. Dave is smart. Dave is young. Erin is round. Erin is smart. Erin is white. Erin is young. Harry is smart. Harry is white. Harry is young. If someone is rough and young then they are blue. Rough people are white. If someone is round then they are young.
Dave is not white.