Well, the code actually wasn't intended to be obfuscated. I've never had much of an interest in writing obfuscated perl, and haven't read the node you mentioned. (Although I expect I will as soon as I'm done posting my reply....)

I started with the mere idea that I wanted to write "My Bonnie Lies Over the Ocean" as a perl poem, and just tried my hardest to force the poem to be syntactically valid. I will admit that it turned out better than I expected. Here's a collection of thoughts that might help to explain how it got into its final form.

I started with:

my $bonnie = "lies_over_the_ocean";           
my $bonnie = "lies_over_the_sea";              
my $bonnie = "lies_over_the_ocean";
[download]

Of course, the compiler complained about multiple declarations of $bonnie within the same scope, so I merely added the requisite braces to make each $bonnie declaration fall into a new scope.

The 0; before the first bring_back() is simply a no-op. It's there because the actual song contains the word "oh" at that point.

I noticed that the words "bring back" are used repeatedly throughout the song, and made an analogy between lyrics and code. As a rule, oft-used pieces of code should be stuck within a function. Hence, I created a bring_back() function and called it repeatedly. It just "worked out" to have nested calls to bring_back(), since that fits the flow of the actual song. The calls to bring_back() have the added advantage of setting up new scopes such that I can declare $bonnie again. The 0,'s within the function calls continue the tradition set up earlier; they use the number 0 to represent the phonetic "oh"'s that are present in the real song, while keeping the code syntactically valid.

I called each bring_back() with whatever arguments fit the song.

At this point, I created an empty sub bring_back {} that did nothing, and thought my work was done.

I then decided it would be nice for the poem to actually output something, and decided that bring_back() should be the place to do it. The obvious problem was getting the output to print only once, since bring_back() gets called 7 times. I decided I'd use the number of arguments passed to bring_back() as the criteria for printing, and simply toyed with bring_back()'s return value until I got a unique number of arguments passed (5) on the last call.