There is beauty in the fact that Lisp expressions are called forms.
Form is really fundamental. And so are Lisp expressions.
While Lisp expressions use a limited syntax (s-expressions) they are nevertheless fundamentally free-form.
One day we will all be programming in 2D graphics, and Lisp already accommodates these. To Lisp, it doesn't make a difference whether a form is 1D or 2D.
A form is simply something to be evaluated.