use Test2::V0;
use v5.40;

my @lists= (
  [qw( X P Y )],
  [qw( X B Y N )],
  [qw( P B N )],
  [qw( X B P N )],
  [qw( X B P Y )],
  [qw( A Z )],
  [qw( A K L )],
);

my $combined= fancy_algorithm(@lists);
is( $combined, [qw( X B P Y N A Z K L )] );