Yes, I already had something like that in my original solution.

But what I meant was determining the max size to use:

my $h3_columns = 2 ; # use List::Util qw(max) ; max (each array size) 
+= 2
$hash3{$_} = [ (0) x $h3_columns ] for @keys3_origin ;
[download]

I will find a solution for that, no worries. But that will be after this weekend.