package Point;

use strict;
use warnings;
use Data::Dumper;

my @data = (...) #see data_sets below

my @new_data;

while ( @data ) {
  my $item = shift @data;

  my $match;
  foreach (0 .. $#data ) {
   if ( $data[$_][0]{X} == @{$item}[-1]->{X} and
        $data[$_][0]{Y} == @{$item}[-1]->{Y} ) {
     $match = ['front', $_ ];
     last;
   }
   if ( $data[$_][-1]{X} == @{$item}[0]->{X} and
        $data[$_][-1]{Y} == @{$item}[0]->{Y} ) {
     $match = ['end' , $_ ];
     last;
   }
  }

  if ( defined $match ) {
    if ( @{$match}[0] eq 'front' ) {
       splice @{$data[@{$match}[1]]},0,1,@{$item};
    }
    else  {
       splice @{$data[@{$match}[1]]},-1,1,@{$item};
    }
  }
  else  {
    push @new_data,$item;
  }
}

print Dumper \@new_data;