Anchor: A person in a parka is walking on a sidewalk.
Entailed: A person is walking on a sidewalk.
Contradiction: A dog is running on a sidewalk.
Contradiction: She stayed silent and said nothing. 
Contradiction: Case studies don't compare people that have different treatments.
Contradiction: No, I am not talking about the thing etched on the rear view morror.
Contradiction: The dining room is at the top of the stairs.