* `(list)` and `'()` both evaluate to the empty list
* `(null? lst)` tests whether `lst` is the empty list
* non-empty lists are implemented as pairs whose second member is a list
- * `'() '(1) '(1 2) '(1 2 3) are all lists
+ * `'()` `'(1)` `'(1 2)` `'(1 2 3)` are all lists
* `(list)` `(list1)` `(list 1 2)` `(list 1 2 3)` are the same lists
* `'(1 2 3)` and `(cons 1 '(2 3))` are pairs that are also lists (the same list)
* `(pair? lst)` tests whether `lst` is a pair; if `lst` is a non-empty list, it will also pass this test; if `lst` fails this test, it may be because `lst` is the empty list, or because it's not a list or pair at all