use strict;
use warnings;

my $stuff = [ 'a', 'b', 'c', 'd' ];

sub cyclist {
  my $array = shift;
  my $pos = -1;
  return sub { return $$array[++$pos % @$array]; }
}

my $cyclestuff = cyclist $stuff;

print $cyclestuff->() for 1..30;
print "\n";
$$stuff[0] = 'A';
print $cyclestuff->() for 1..30;
print "\n";