Anne is quiet. Anne is young. Dave is blue. Dave is round. Dave is white. Dave is young. Fiona is rough. Fiona is round. Gary is blue. Gary is white. If Dave is rough and Dave is white then Dave is blue. Young people are round. White people are quiet. All quiet people are nice. All rough, young people are blue. If Fiona is round then Fiona is white. All nice people are young. Quiet people are nice.
Fiona is not young.