#!/usr/bin/perl -w

use strict;

use v5.10;

my @pairs;

sub addpairs {

my ($m, $n) = @_;

return if 0 == $m && 1 == $n;

say "$m, $n";

push @pairs, [$m, $n];

}

addpairs 1, 2;

while (@pairs) {

my $pair = shift @pairs;

my ($m, $n) = @$pair;

addpairs 2 * $m - $n, $m;

addpairs 2 * $m + $n, $m;

addpairs $m + 2 * $n, $n;

}