Anchor: For example, a discount could be given for mail presorted into packages, each package being for one 5-digit ZIP Code area.
Entailed: There could be a discount if the mail was presorted by zip code. 
Contradiction: It's impossible for the mail to be presorted. 
Contradiction: The people are stacking bricks
Contradiction: A person has fruit on a street
Contradiction: It is closed to the public, you may enter by invitation only.
Contradiction: The animal plays in the water.