title: interact with an interface?
body: <p>from what i've read it seems that one can interact with an interface?</p>
  
  <p>eg. lets say that i've got an interface with an empty method "eat()"</p>
  
  <p>then 2 subclasses are implementing this interface.</p>
  
  <p>can my controller interact with only the interface and use it's eat() method?</p>
  
  <p>have a look at the picture in this link <a href="http://sourcemaking.com/design_patterns/strategy" rel="noreferrer">strategy</a></p>