Rolling Text in Perl

rollingtext.pl

#!/usr/bin/perl
use 5.010;
use Time::HiRes qw (sleep);

sub rand_letter() {
    @letters=(A..Z,a..z," ",".",",");
    return $letters[rand @letters];
}

my $final_form = "Hello world";

my @final_form = split //, $final_form;
my @done;
foreach (@final_form){
    my $letter=rand_letter();
    my $to_match = $_;
    say $to_match;
    while ($letter ne $to_match){
        $letter=rand_letter();
        print "\033[2J";    #clear the screen
        print "\033[0;0H";
        print @done;
        say $letter;
        sleep(.02);
    }
    push @done, $letter;
    $i++;
}