my @pts = (
	     [$x1 + $ba, $y1 - $b1],
	     [$x1 - $ba, $y1 - $b1],
	     [$x1-2*$ba, $y1      ],
	     [$x1 - $ba, $y1 + $b1],
	     [$x1 + $ba, $y1 + $b1],
	     [$x1+2*$ba, $y1      ],
	    );
my $poly = new GD::Polygon;
$poly->addPt(@{$pts[$_]}) for (0..5);
$im->polygon($poly, $cols{BG});