use strict;
use warnings;

my @file = (
'1	2	3	4',
'5	6	7	8',
'9	10	11	12',
'13	14	15	16');

my @data;
foreach my $line (@file) {
	my @fields = split(/\t/,$line);
	for (my $x = 1 ; $x <= $#fields ; $x++) {
		push @{$data[$x-1]},  [$fields[0],$fields[$x]];
	}
	
}

for ( my $x = 0 ; $x <= $#data; $x++) {
	open(FH,">OUTPUT_$x") or die "$!\n";
	foreach my $fields ( @{$data[$x]} ) {
		print FH "$fields->[0] $fields->[1]\n";
	}
	close FH;
}