Charlie is big. Charlie is green. Charlie is round. Dave is green. Dave is rough. Dave is round. Dave is smart. If Charlie is blue and Charlie is round then Charlie is big. All green, rough things are big. All rough things are young. All round things are rough. All blue, green things are rough. All green things are young. If something is rough then it is green. If something is smart and round then it is green.
Dave is not blue.