Can you derive a clue from the following?

$lim=3;
while(<DATA>)
{
    if(0 == ($ctr % $lim) )
        {
            print "\n\nNext group of $lim is...\n";
        }
        print ;
           $ctr++;
}
__DATA__
one
two
three
four
five
six
seven
eight
nine
ten
[download]

This is just to "send" the clue. No boundary conditions tested :)