text: class Displayable(object):
      """
      Base class for any object to be displayed on game field.
      object_name
  
      get_name(self)
      display(self, another_displayable)
      get_shape(self)
      get_coordinates(self)
      """
  
      def __init__(self, object_name):
          self.object_name = object_name
  
      def get_name(self):
          return self.object_name
  
      # TODO: choose some particular display object type
      def display(self, display_object):
          """
          Draws this object on display object (e.g. some
          drawing panel passed.)
          """
          return
  
      def get_shape(self):
          """Returns fully described shape of this object."""
          return
  
      def get_coordinates(self):
          """
          Returns tuple (x, y) containing coordinates of point
          considered to be center of this object.
          """
          return
  