use strict;
use warnings;

my @source = (
        [1, 2, 3],
        [4, 5, 6],
        [7, 8, 9]
);

my @bl1;
print "BL1:\n";
push @bl1,@$_ for @source;
print "$_\n" for @bl1;

my @bl2;
print "BL2:\n";
push @bl2,$_ for @source;
print "@$_\n" for @bl2;