All,
Earlier today, I was faced with a problem that amounted to:

for my $let (keys %hash) {
    for my $num (keys %{$hash{$let}}) {
        for my $name (keys %{$hash{$let}{$num}}) {
            print join(',', $let, $num, $name, $hash{$let}{$num}{$name
+}), "\n";
        }
    }
}
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The trouble was, the data structure was going to be an arbitrary number of levels deep. My first inclination was to reach for Algorithm::Loops but it didn't seem like a good fit. My second idea was to write an iterator (see Arbitrarily Nested Loops) but I wanted a coworker who is just learning perl (former C++ developer) to be able to maintain it. In a few minutes, I came up with a recursive solution which surprised me.

On my way home, I thought of several other ways of doing it and I was wondering how others might solve the problem. That is my question - how would you do it? I have provided my recursive solution below to get the ball rolling.