,-----------------------------------.       
       |==main.Event                       |       
       |-----------------------------------|       
       |Event is a gathering with greeters.|       
       |                                   |       
       `-----------------------------------'       
                         |                         
                         |                         
,-------------------------------------------------.
|==main.Greeter                                   |
|-------------------------------------------------|
|Greeter is the type charged with greeting guests.|
|                                                 |
`-------------------------------------------------'
                         |                         
                  ,------------.                   
                  |main.Message|                   
                  |------------|                   
                  `------------'