If you have a copy of O'Reilly's Perl Bible - Camel 3, check out page 94 - "Multiplicative Operators." Here's a quick synopsis:

my $char = '*';
print $char x 5;  # prints "*****"
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HINT: Once you understand that part, you can solve your whole problem by using the multiplicative operator twice, rather than using for loops.

If you don't have Camel 3, go get it if you plan to do any Perl in the future. It's better than sliced bread. :)