use strict;

sub make_ref {
  my $name = shift;
  my $i = 99;
  return sub {
    print "ref $name: ",$i++,"\n";
  }
}

my $ref1 = make_ref("sub1");
my $ref2 = make_ref("sub2");

for (1 .. 10) {
  $ref1->();
  $ref2->() if $_ % 2 == 0;
}

##</code><code>##

ref sub1: 99
ref sub1: 100
ref sub2: 99
ref sub1: 101
ref sub1: 102
ref sub2: 100
ref sub1: 103
ref sub1: 104
ref sub2: 101
ref sub1: 105
ref sub1: 106
ref sub2: 102
ref sub1: 107
ref sub1: 108
ref sub2: 103