Dave is green. Dave is red. Dave is rough. Dave is young. Fiona is cold. Fiona is rough. Fiona is white. If something is white then it is rough. If something is rough and cold then it is smart. If something is red and cold then it is young. If something is red and young then it is green. All smart things are young. If something is smart and rough then it is red.
Fiona is not smart.