,--------------------------------.                    
                |Bird                            |                    
                |--------------------------------|                    
                |{abstract} getPlumage() : String|                    
                `--------------------------------'                    
                                 |                                    
                                 |                                    
,---------------.  ,-------------------------.   ,-------------------.
|EuropeanSwallow|  |AfricanSwallow           |   |NorwegianBlueParrot|
|               |  |-------------------------|   |-------------------|
`---------------'  |numberOfCoconuts : number|   |voltage : number   |
                   `-------------------------'   `-------------------'