(define (over-or-under num1 num2)
  (cond 
    ((< num1 num2) -1)
    ((= num1 num2) 0)
    (else          1)))

(define (make-adder num)
  (lambda (inc) (+ inc num)))

(define (composed f g) (lambda (x) (f (g x))))

(define lst
        (cons (cons 1 nil)
              (cons 2 (cons (cons 3 (cons 4 nil)) (cons 5 nil)))))

(define (duplicate lst)
  (if (null? lst)
      lst
      (cons (car lst)
            (cons (car lst) (duplicate (cdr lst))))))
