$ ./render_thermometer.pl
$VAR1 = 'GD::Graph::Thermometer';
$VAR2 = bless( do{\(my $o = 137557384)}, 'GD::Image' );
$VAR3 = {
          'mercury_color' => undef,
          'background_color' => undef,
          'outline_color' => undef,
          'text_color' => [
                            0,
                            0,
                            255
                          ]
        };
Usage: GD::Image::colorAllocate(image, r, g, b) at /home/hesco/sb/GD-Graph-Thermometer/lib/GD/Graph/Thermometer.pm line 133.