#!/usr/bin/perl

# https://perlmonks.org/?node_id=1227147

use warnings;
use strict;

my $pattern = 'FTTF';

my @result = grep {
                $pattern =~ /(?!$)/g;
                $pattern =~ /./g;
                $& eq 'T'
                } 0 .. 12;

print "@result\n";
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