Anchor: A skateboarder catches air over a dumpster as one friend observes and the other friend jests.
Entailed: A person is skateboarding outside
Contradiction: A girl is rollerskating at a party.
Contradiction: A skateboarder is drinking a soda
Contradiction: The three friends do a simultaneous skating trick.
Contradiction: a kid does a cartwheel in a gym
Contradiction: Nobody is observing