No the reversal in my above comments only applied to the example, not the way I defined internal vs. external representations. Sorry for the confusion. My poi

No the reversal in my above comments only applied to the example, not the way I defined internal vs. external representations. Sorry for the confusion. My point is that you can't tell by looking at the defun in my above comment whether you're looking at Lisp source code or the parse tree (represented as a nested list) for that source code. The same would not be true in C where the external representation of the parse tree would be the C syntax for initializing some set of nested struct's. That would look very different than the source code itself.