#!/usr/bin/perl
...
my @polygon = build_polygon($num_points, $radius);
print_svg_polygon(@polygon);
exit;

sub build_polygon {
...

##</code><code>##

sub calcMagic
{
    my ($n) = @_;
    my $m   = -1;
    my $mod = 1;

    for(1..$n)
    {
        $mod += $m;
        $m = nextMagic($m);
    }
    return $mod;
}