Anchor: One could deposit a letter at the post office in a city for transportation to the post office in another city where the recipient would call for it.
Entailed: Letters can be delivered between post offices.
Contradiction: Letters may only be delivered between homes.
Contradiction: The three people are on a roller coaster.
Contradiction: Brown dog digging through the snow.
Contradiction: No, I haven't, but I heard it's pretty good.
Contradiction: The singer posed in the spotlight.