use 5.010;

# See http://en.wikipedia.org/wiki/Orders_of_magnitude_(area).
use constant AREA_OF_THE_HEAD_OF_A_PIN  => 2.000; # square millimetres

# Based on the assumption that angels are non-corporeal.
use constant SPACE_TAKEN_UP_BY_ANGEL    => 0.000; # square millimetres 

my $angels = 0;
my $area_remaining = AREA_OF_THE_HEAD_OF_A_PIN;

while ($area_remaining > 0)
{
	$angels++;
	$area_remaining -= SPACE_TAKEN_UP_BY_ANGEL;
}

say "$angels angels can fit on the head of a pin";