> This solution looks extremely similar to the previous one, which is a good thing. Our requirements have experienced a small change (reversing the traversal order) and our solution has responded with a small modification.

Now do breadth-first traversal. With the iterative approach, you just replace the stack with a queue. With the recursive approach, you have to make radical changes. You can make either approach look natural and elegant if you pick the right example.

> Now do breadth-first traversal. With the iterative approach, you just replace the stack with a queue. With the recursive approach, you have to make radical changes.

The reason is that no programming language that is in widespread use has first-class support for co-recursion. In a (fictional) programming language that has this support, this is just a change from a recursive call to a co-recursive call.