my @emps=map "employee_$_",1..5;
my @codes='v'..'z';
my $n=3;
for my $j (0..$n-1) {
  for my $i (0..$#emps) {
    print $emps[$i],":",$codes[($i+$j) % @codes],"\n";
  }
  print "\n";
}
__END__
employee_1:v
employee_2:w
employee_3:x
employee_4:y
employee_5:z

employee_1:w
employee_2:x
employee_3:y
employee_4:z
employee_5:v

employee_1:x
employee_2:y
employee_3:z
employee_4:v
employee_5:w