List utilities
- (cons 1 (cons 2 ())) -> (1 2)
 
cons produces a new cons cell (essentially a pair of two values). Cons cells (or pairs) form the basis of linked lists,
and therefore all source code.
car returns the first item of a cons cell.
- (cdr '(1 2 3 4)) -> (2 3 4)
 
cdr returns the second item of a cons cell.
- (list 1 2 3 4) -> (1 2 3 4)
 
list is a function takes any number of parameters, and produces a list containing only those elements in the order passed to it.