data available?                          
                                                                                                 
                                                                                                 
                                                                                                 
                                                                                                 
                                                                                        read data
                                                                                                 
                                                                                                 
                                                                                                 
                                                                                                 
                                                                                                 
                                                                                                 
                                                            generate diagrams