多態とはどういう意味ですか.

    :

         ,

  ,     ,      n  ,

  :    ,

      ;

        ,       

     ,

        ,

    ,

       

...

         !

  a =   
  b =    
  c =   

     ,     " "  ,            ,

            ,      .

      [            ],      " "   ,     ,        

        .

     :

1.         

2.      ,           .

        ,

          ,        shape(),           .      [  ,  ,   ],    shape  ,        ,

                 ,

[      =       ]

for example:

  a = new   ();

  a = new   ();

  a = new   ();

  a = new   ();

       ,     a     ,

a.shape(),         .

       

  a = new   ();

  a.shape         ,         

   a = new   ();    a.shape