void Update()
        {
            if (Input.GetKeyDown(KeyCode.P))
            {
                IUnit prey;
                int   numberOfPrey = 5;
                m_Preys = new IUnit[numberOfPrey];

                for (int i = 0; i < numberOfPrey; i++)
                {
                    prey = new Prey();
                    m_Grid.AddToRandomnPosition(prey);
                    m_Preys[i] = prey;

                    Debug.Log("A prey was spawned @ square: " + m_Preys[i].GetGridPosition());
                }
            }

            if (Input.GetKeyDown(KeyCode.H))
            {
                IUnit predator;
                predator = new Predator();
                m_Grid.AddToRandomnPosition(predator);
                Debug.Log("A predator was spawned @ square: " + predator.GetGridPosition());

                int closest = m_Grid.FindClosest(predator, m_Preys);
                Debug.Log("The closest prey is @ square: " + closest);
            }
        }