sub BlackBody {
    ColormapHtml( BlackBodyMap() );
    ColormapHtml( GreyscaleMap() );
}
sub ColormapHtml {
    my $blackbody = shift;
    print "<table>";
    while(@$blackbody){
        print "<tr>";
#~         for(1..8){
#~         for(1..16){
        for(1..32){
            my $color = shift @$blackbody;
#~             my $hex = join '', map { pack 'H*', $_ } @$color;
            my $hex = rgb2hex( @$color );
#~             print qq[<td bgcolor="#$hex"><font color="#$hex">$hex</font></td>];
            print qq[<td bgcolor="#$hex"><font color="#$hex">_</font></td>];
        }
        print "</tr>";
    }
    print "</table>";
}
sub rgb2hex {
#~     my( $r, $g, $b ) = @_;
    sprintf '%02x%02x%02x', @_;
}
sub BlackBodyMap {
    my $one = [ 255, 0, 0 ] ;
    my $two = [ 255, 255, 0 ];
    my @colormap = (
        YuckFoo( 85, [0,0,0] => $one ),
        YuckFoo( 85, $one => $two ),
        YuckFoo( 86, $two => [255,255,255] ),
    );
    return \@colormap;
}
sub GreyscaleMap {
    return [ YuckFoo(256, [0,0,0] => [255,255,255] ) ];
}
sub YuckFoo {
    my( $steps, $beg, $end) = @_;

   # RGB rate of change from beginning to ending color
    my @delta = ( 
        ($$end[0] - $$beg[0]) / ($steps-1),
        ($$end[1] - $$beg[1]) / ($steps-1),
        ($$end[2] - $$beg[2]) / ($steps-1),
    );
   
# Calculate colors using beginning color and rate of change
    my $i = 0;
    my @gradient;
    while($i < $steps) {
        my $color = [
            $$beg[0] + $i * $delta[0],
            $$beg[1] + $i * $delta[1],
            $$beg[2] + $i * $delta[2]
        ];
        push @gradient, $color;
        $i++;
    }
    return @gradient;
}