use strict;
use warnings;

my @cache;
my $n_min=2;
my $n_max=6;


while (my $line =<DATA>) {
    chomp $line;
    push @cache, $line;
    for my $n ($n_min..$n_max) {
        print "$n: @cache[-$n .. -1]\n"   # last n of cache
            if @cache >= $n;
    }
    shift @cache if @cache == $n_max;     # keep cache at max size
} 


__DATA__
One
Two
Three
Four
Five
Six
Seven
Eight
Nine
Ten