Anchor: I must be mad to think of such a thing." Poirot nodded, as if satisfied. 
Entailed: Poirot seemed to think he was right in dismissing the idea.
Contradiction: "I knew it, I was right!" exclaimed Poirot with certainty.
Contradiction: No diving is permitted at the nearby islets.  
Contradiction: Newspapers have to be recycled.
Contradiction: The skateboarder is riding roller-blades.
Contradiction: People are at the market.