var oMallardDuck = new MallardDuck();
var oDuckCall = new DuckCall();
var oRedheadDuck = new RedheadDuck();
var oRubberDuck = new RubberDuck();
var oGoose = new Goose();
var oGooseAdapter = new GooseAdapter(oGoose);
console.log("Duck simulator:");
oMallardDuck.quack();
oDuckCall.quack();
oRedheadDuck.quack();
oRubberDuck.quack();
oGooseAdapter.quack()