@color = qw|red green blue|;

$can->create ( 'rectangle',
        $X,   $Y, 
        $X+1, $Y+1,
        -fill => $color[1];
    );

##</code><code>##

$widget->setPalette('red');

##</code><code>##

($r, $g, $b) = $widget->rgb("red");
$hex_color = "$r$g$b$";
$mw->Button( -background => $hexcolor);