--------------------->  an anthem                                                   
                                                                                    
                             |                                                      
                             |                                                      
                             |                                                      
                             |                                                      
                             |                                                      
                             |                                                      
                              -------------------> in a vacuum                                          
                                                                                    
                                                           |                        
                                                           |                        
                                                           |                        
                                                           |                        
                                                           |                        
                                                           v