use strict;
use warnings;

my @month_name = qw(
    January February March April May June July August September
    October November December
    );
    
for my $startMonthIdx (0 .. 11) {
    my @sel = @month_name[$startMonthIdx .. 11, 0 .. $startMonthIdx - 1];

    print "$startMonthIdx: @sel\n";
}

##</code><code>##

0: January February March April May June July August September October November December
1: February March April May June July August September October November December January
2: March April May June July August September October November December January February
3: April May June July August September October November December January February March
4: May June July August September October November December January February March April
5: June July August September October November December January February March April May
6: July August September October November December January February March April May June
7: August September October November December January February March April May June July
8: September October November December January February March April May June July August
9: October November December January February March April May June July August September
10: November December January February March April May June July August September October
11: December January February March April May June July August September October November