Text: The Accademia's uncontested star, the great David (which once stood in the Piazza della Signoria, now substituted by a life-size copy), provides the perfect object lesson of the finished product, a hero infused with all the contained energy needed to hurl that stone at Goliath.
Entailment: The statue of David once stood at the Accademia, but it has now been replaced by a copy.
Contradiction: In the Piazza della Signoria, the original statue of David still stands where it was first erected.