This visualization actually might simplify the coding of a morse code converter (i.e. Perl Golf?). I read about it in "Code" (Microsoft Press, but perhaps out of print) and found it to be an intriguing way to visualize Morse code. It enables you to write a simple state machine instead of a more complex pattern matcher.

BTW, tr doesn't require set brackets, but including them would just harmlessly convert them to same, right?     tr/[a-z]/[A-Z]/ Is theoretically equivalent to:     tr/[]a-z/[]A-Z/ Which is much like:     tr/[]/[]/; tr/a-z/A-Z/ Right? Although you would probably use uc instead.