Bob is quiet. Bob is red. Bob is rough. Bob is white. Harry is red. Harry is round. Harry is white. All red, round things are furry. All round things are red. If something is green and round then it is red. Red, rough things are quiet. All red, furry things are round. All green, rough things are white. Furry, white things are quiet. If something is quiet and green then it is rough.
Bob is not white.