I&#x27;d assume laymen think in terms of combinators, ie like map (do this operation to all the things I have), or filter (through out all the widgets that fail the test).  Thinking in terms of indices is pretty painful.<p>&gt; Those are just abstracted loops though, not recursion.<p>Map and filter on a tree is about as recursive as it gets.  Loops are the special case of recursion that does work well on linear data structures like linked lists and arrays, yes.