premise: Two boys are gesturing to one another in front of a Coca-Cola vending machine. hypothesis: A group of girls trying to get a soda out of the Pepsi vending machine.
contradiction: The people involved are either two boys or a group of girls; they are either gesturing to one another in front of or trying to get a soda from a vending machine, and they machine is either Coca-Cola or Pepsi, but not both.