#!/home/ben/software/install/bin/perl
use Z;
use Math::Trig;

my $twof = 4*pi/5;
my $s144 = sin ($twof);
my $c144 = cos ($twof);
my $t144 = $s144 / ($c144 - 1);
my $x = (cos (2*pi/5) - 1) * $t144;
my $y = 1 + $x / $t144;
my $exy = cos (deg2rad (72));
my $factor = sqrt ($x**2 + $y**2);
my $radius = 100;
my $max = 10;
my @points;
for my $s (1..$max) {
    my $a = 2*pi*$s/$max;
    my $r = $radius;
    if (($s % 2) == 1) {
	$r *= $factor;
    }
    my $x = sin ($a) * $r;
    my $y = -cos ($a) * $r;
    push @points, [$x, $y];
}
print <<EOF;
<svg height="800" width="800" xmlns="http://www.w3.org/2000/svg">
EOF
print "<polygon points='";
for my $point (@points) {
    printf ("%.2f %.2f\n", $point->[0], $point->[1]);
}
print "'/>\n";
print <<EOF;
</svg>
EOF