(define (square-list-bug1 items)
  (define (iter things answer)
    (if (null? things)
        answer
        (iter (cdr things)
              (cons (square (car things))
                    answer))))
  (iter items '()))

; 1 ]=> (square-list-bug1 '(1 2 3 4 5))
; 
; ;Value: (25 16 9 4 1)

; This version of square list builds answer starting from the first item and
; appending following results to the front of answer. This causes the result
; to be reversed.

(define (square-list-bug2 items)
  (define (iter things answer)
    (if (null? things)
        answer
        (iter (cdr things)
              (cons answer (square (car things))))))
  (iter items '()))

; 
; 1 ]=> (square-list-bug2 '(1 2 3 4 5))
; 
; ;Value: (((((() . 1) . 4) . 9) . 16) . 25)

; Because this version prepends the current partial answer - which is a list -
; to the front of the next partial answer, the final result will have a nested
; list as an element rather the being a list of numbers. The only input this
; function is correct for is the empty list.