use Alorithm::Loops;

sub transpose_AoS {
   # [                   [
   #                        'aeh',
   #    'abcd',             'bfi',
   #    'efg',     ==>      'cgj',
   #    'hijkl',            'd k',
   #                        '  l',
   # ]                   ]

   return [
      MapCarU { join('', map { defined($_) ? $_ : ' ' } @_) }
         map { [ /(.)/sg ] }
            @{$_[0]}
   ];
}