my $ref = [ [ 1..3], [9..11] ];
for my $first ( @$ref ){
   for my $item ( @$first ){
      print $item;
   }
}
__END__
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##</code><code>##

my $ref = [ [ 1..3], [9..11] ];
for my $xi ( 0 .. $#{ $ref } ){
   for my $yi( 0 .. $#{ $ref->[ $xi] } ){
      print $ref->[ $xi ][ $yi ];
   }
}
__END__
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