This chapter of the book takes a look at delegation & protocols. In this...

... commit a text filed has been added to the BNRHypnosisViewController. BNRHypnosisViewController now conforms to UITextFieldDelegate protocol, methods are optional, we added textFieldShouldReturn. This method takes the text entered by the user and passes it to drawHypnoticMessage which in turn takes the text passed by textFieldShouldReturn an randomly prints it across the view.