ズンドコキヨシ with Perl ref: http://qiita.com/shimx/items/51da4b56bca1ac2cb269

kiyoshi.pl

use strict;
use warnings;

sub kiyoshi {
  my @zd  = my ($z, $d) = ('ズン', 'ドコ');
  my $str = join('', (my @kys = ($z, $z, $z, $z, $d)));
  my $cnt = 0;
  my @word;

  while ( join('', @word) ne $str ) {
    shift @word if $#word >= $#kys;
    push @word, $zd[rand(@zd)];
    print $word[$#word];
    $cnt++;
  }
  print "キ・ヨ・シ！\n($cnt回ズンドコしました)\n";
  return;
}

kiyoshi();