The <a href="https://en.wikipedia.org/wiki/Pinocchio_paradox" class="extiw" title="w:Pinocchio paradox">w:Pinocchio paradox</a>. When Pinocchio says "My nose grows now" it creates a <a href="https://en.wikipedia.org/wiki/Liar_paradox" class="extiw" title="w:Liar paradox">Liar sentence</a> and makes Pinocchio's nose grow if and only if it does not grow.
Carlo Chiostri, <a href="//commons.wikimedia.org/wiki/User:Mbz1" title="User:Mbz1">User:Mbz1</a>
2012-07-02
File:Pinocchio paradox.svg