On this topic, are there any other good examples of languages that are as homoiconic as lisp? Or is lisp the logical extreme of what you get when you follow that line to its end, so by definition there can "be only one?"
It really seems to come out in the wash that way. We have the concept of use ( and ) to group stuff beaten into us from an early age. Then you can either choose to separate elements with , or with nothing at all. It makes sense that the first element is special. Then you can nest them. And that's it really. How else would you do it? Lisp is the "it's code by default" model and Forth is the "it's data by default" model.