Then its contrapositive, obtained by interchanging the "if" and "then" clauses" and simultaneously negating them, is

The two statements are exactly equivalent in meaning, as can be determined by the diagram at right. The original statement asserts, in effect, that the oval representing "elephants" is a subset of the "mammals" oval. The contrapositive asserts something that is geometrically equivalent—namely, that the shaded exterior of the "mammals" oval is a subset of the exterior of the "elephants" oval. In a similar way, it is easily seen that the converse of the original statement (formed by interchanging the "if" and "then" clauses) is logically equivalent to the original statement's inverse (formed by negating both clauses).

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