use strict;
use warnings;
use Data::Dumper;

my @x = (0, 18, 36, 0, 18, 36, 0, 18, 36, 0, 18, 36, 0, 18, 36, 0, 18, 36);
my @y = (0, 0, 0, 18, 18, 18, 36, 36, 36, 0, 0, 0, 18, 18, 18, 36, 36, 36);
my @z = (25, 25, 25, 25, 25, 25, 25, 25, 25, 20, 20, 20, 20, 20, 20, 20, 20, 20);


my @sorted = sort { $a->[2] <=> $b->[2] or
                    $a->[1] <=> $b->[1] or
                    $a->[0] <=> $b->[0] }
             map { [ $x[$_], $y[$_], $z[$_] ] } 0 .. $#x;

@x = @y = @z = ();
foreach (@sorted) {
  push @x, $_->[0];
  push @y, $_->[1];
  push @z, $_->[2];
}

print "@x\n@y\n@z\n";