use strict;
use warnings;

my @teams = qw {
    Mice
    Squirrels
    Snails
    Fish
    Frogs
    Bees
    Sparrows
    Snakes
    Camels
    Leeches
};

sub shuffle {
    foreach (my $i = @_; -- $i;) {
        my $r = rand ($i + 1);
        @_ [$i => $r] = @_ [$r => $i];
    }
    @_;
}


my $rounds = shift || 5;

foreach (1 .. $rounds) {
    my @pairing = shuffle @teams;
    while (@pairing) {
        my ($home, $away) = splice @pairing => 0, 2;
        printf "%20s  -  %20s\n" => $home, $away;
    }
    print "---\n";
}
__END__
              Snakes  -                Snails
            Sparrows  -                  Mice
                Bees  -                 Frogs
                Fish  -               Leeches
              Camels  -             Squirrels
---
             Leeches  -                 Frogs
                Mice  -                Snails
                Fish  -                Camels
           Squirrels  -                Snakes
            Sparrows  -                  Bees
---
                Bees  -             Squirrels
                Mice  -               Leeches
               Frogs  -              Sparrows
              Snails  -                Snakes
              Camels  -                  Fish
---
               Frogs  -              Sparrows
              Camels  -             Squirrels
              Snails  -                  Bees
                Fish  -                  Mice
              Snakes  -               Leeches
---
                Mice  -                Camels
                Fish  -                Snails
             Leeches  -                 Frogs
           Squirrels  -                  Bees
            Sparrows  -                Snakes
---