(function() {

  var Person = my.Class({

    STATIC: {
      AGE_OF_MAJORITY: 18
    },

    constructor: function(name, age) {
      this.name = name;
      this.age = age;
    },

    sayHello: function() {
      console.log('Hello from ' + this.name + '!');
    },

    drinkAlcohol: function() {
      this.age < Person.AGE_OF_MAJORITY ?
        console.log('Too young! Drink milk instead!') :
        console.log('Whiskey or beer?');
    }

  });

  myLib.Person = Person;

})();

var john = new myLib.Person('John', 16);
john.sayHello(); //log "Hello from John!"
john.drinkAlcohol(); //log "Too young! Drink milk instead!"

(function() {

  //Dreamer extends Person
  var Dreamer = my.Class(Person, {

    constructor: function(name, age, dream) {
      Dreamer.Super.call(this, name, age);
      this.dream = dream;
    },

    sayHello: function() {
      superSayHello.call(this);
      console.log('I dream of ' + this.dream + '!');
    },

    wakeUp: function() {
      console.log('Wake up!');
    }

  });

  var superSayHello = Dreamer.Super.prototype.sayHello;

  myLib.Dreamer = Dreamer;

})();

var sylvester = new myLib.Dreamer('Sylvester', 30, 'eating Tweety');
sylvester.sayHello(); //log "Hello from Sylvester! I dream of eating Tweety!"
sylvester.wakeUp(); //log "Wake up!"

my.extendClass(myLib.Dreamer, {

  touchTheSky: function() {
    console.log('Touching the sky');
  },

  reachTheStars: function() {
    console.log('She is so pretty!');
  }

});

 myLib.ImaginaryTraveler = my.Class({
  travel: function() { console.log('Traveling on a carpet!'); },
  crossOceans: function() { console.log('Saying hi to Moby Dick!'); }
});

(function() {

  //Dreamer extends Person implements ImaginaryTraveler
  var Dreamer = my.Class(Person, ImaginaryTraveler, {

    constructor: function(name, age, dream) {
      Dreamer.Super.call(this, name, age);
      this.dream = dream;
    },

    ...

  });

  myLib.Dreamer = Dreamer;

})();

var aladdin = new Dreamer('Aladdin');
aladdin instanceof Person; //true
aladdin instanceof ImaginaryTraveler; //false
aladdin.travel();
aladdin.wakeUp();
aladdin.sayHello();

var Person = my.Class({

  //you can now call the constructor with or without new
  constructor: function(name, city) {
    if (!(this instanceof Person))
      return new Person(name, city);
    this.name = name;
    this.city = citye;
  }

});