private boolean fieldFree(int positionY, int positionX) {
        if (positionY < Simulation.N && positionX < Simulation.N
                && positionY > -1 && positionX > -1
                && (!field[positionY][positionX].isBoxingPlant()
                        || (positionY == startPosY && positionX == startPosX)) && field[positionY][positionX].robotID() == 0) {
            return true;
        }

        return false;
    }