sub genRotar {
    my( $pos, @vals )= ( 0, @_ );
    return sub {
        $pos= 0   if  @vals <= $pos;
        $vals[$pos++]
    }
}
sub Rotar::TIESCALAR {
    shift; return bless genRotar( @_ ), 'Rotar';
}
sub Rotar::FETCH { $_[0]->(); }
my $rowcolor;
tie $rowcolor, 'Rotar', '#FF0000', '#00FF00', '#0000FF';
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Then just append the code you already have above.

        - tye (but my friends call me "Tye")