The distinction between a linked list and a binary tree is in the eye of the beholder. One of the brilliant things about s-expression syntax is that (a b c) is

The distinction between a linked list and a binary tree is in the eye of the beholder. One of the brilliant things about s-expression syntax is that (a b c) is equivalent to (a . (b . (c . nil)))) so there is no distinction between binary trees and linked lists (whose elements can be other linked lists) other than that to be a "proper" list it has to be null-terminated.