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#!/usr/bin/perl

# http://perlmonks.org/?node_id=1211055

use strict;
use warnings;
use Data::Dump 'pp';

my @a = (1, 2, 3);
my @b = ("a", "b");

my @bc = map [ split // ], glob +('{' . join(',', @b) . '}') x @a;

my @c = map { my $t = $_; [ map [ $_, $t->[$_-1] ], 1..@a ] } @bc;

pp @c;
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Outputs:

(
  [[1, "a"], [2, "a"], [3, "a"]],
  [[1, "a"], [2, "a"], [3, "b"]],
  [[1, "a"], [2, "b"], [3, "a"]],
  [[1, "a"], [2, "b"], [3, "b"]],
  [[1, "b"], [2, "a"], [3, "a"]],
  [[1, "b"], [2, "a"], [3, "b"]],
  [[1, "b"], [2, "b"], [3, "a"]],
  [[1, "b"], [2, "b"], [3, "b"]],
)
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