# each Database::XXX class decorates the database
  # arg passed during instantiation, and any methods it
  # doesnt recognise are passed through to the decorated 
  # database. 
  # All done by making the Database:XXX classes inherit
  # from our Decorator class.
  # This code illustrates how this looks to users
  # of the database classes.
 
  my $db = Database->new( database => 'sussex' );
  
  # add colour managment sprocs to database
  my $colour_db = Database::Colour->new( db => $db );

  # Database::Colour knows hues hue (implements Rainbows)
  $colour_db->generateRainbow();
  ... 
  checkFlowerColours( db => $colour_db );
 
  sub checkFlowerColours {
    my %arg = @_;

    # in this context, we need to add some
    # garden compost to the colour enabled database
    my $garden_db = Database::Garden->new( db => $arg{db} );

    # sameColour is from Database::Colour
    if ( $garden_db->sameColour( $garden_db->getLawnColour(), 'brown' ) {
      # action is from Database::Garden
      # but hosePipeBan is from Database('sussex')
      $garden_db->waterPlants()
        unless $garden_db->hasHosePipeBan();
    }
  }