void OnEnable()
        {
            Debug.Log ("------------------");
            Debug.Log ("CHAIN OF RESPONSIBILITY DESIGN PATTERN");

            // create calculation objects that get chained to each other in a sec
            Chain calc1 = new AddNumbers();
            Chain calc2 = new SubstractNumbers();
            Chain calc3 = new DivideNumbers();
            Chain calc4 = new MultiplyNumbers();

            // now chain them to each other
            calc1.SetNextChain(calc2);
            calc2.SetNextChain(calc3);
            calc3.SetNextChain(calc4);

            // this is the request that will be passed to a chain object to let them figure out which calculation objects it the right for the request
            // the request is here the CalculationType enum we add. so we want this pair of numbers to be added
            Numbers myNumbers = new Numbers(3, 5, CalculationType.Add);
            calc1.Calculate(myNumbers);

            // another example:
            Numbers myOtherNumbers = new Numbers(6, 2, CalculationType.Multiply);
            calc1.Calculate(myOtherNumbers);

            // or pass it to some chain object inbetween which will not work in this case:
            Numbers myLastNumbers = new Numbers(12, 3, CalculationType.Substract);
            calc3.Calculate(myLastNumbers);
        }