String::LCSS provides the function "lcss" to ferret out the longest common
substring shared by two strings passed as arguments.  "undef" is returned
if the susbstring length is one char or less.

This is an algorithm I wrote some years ago in C and thought it might be
fun to rewrite in Perl since CPAN seemed to be in want of such a thing.
There is probably a Perlier way to write the algorithm, but...

Not much planned for the future, perhaps changing the args of the "lcss"
function to accept an arbitrary lenght array would be useful.  We wait
then for a rainy day...
