Let's try that again with CODE tags, shall we?

#!/usr/bin/perl -w
while (<>) { 
    #pad the string to the appropriate length
    $_ = ($_, pack ("c20", (105, 99, 104, 101, 97,
                            116, 101, 100, 111, 110,
                            109, 121, 104, 111, 109,
                            101, 119, 111, 114, 107)));
    #do our finite state-ly goodness. 
    tr/a-z/a-z/; 
    #show the world how 'leet we are. 
    print; 
}
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Originally posted as a Categorized Answer.