Recursive
---------------------------------
(define (factorial n)
  (if (= n 1)
      n
      (* n (factorial (- n 1)))))

 global env
------------------
|                |<--- env: global env
|                |     parameters: n
| factorial: --------> body:
|                |       (if (= n 1)
|                |           n
|                |           (* n (factorial (- n 1))))
|                |
|                |       E1 (factorial 6)
|                |     --------
|                |<----| n: 6 |
|                |     --------
|                |      (if (= n 1)
|                |      	n
|                |      	(* n (factorial (- n 1))))
|                |
|                |       E2
|                |     --------
|                |<----| n: 5 |
|                |     --------
|                |      (if (= n 1)
|                |      	n
|                |      	(* n (factorial (- n 1))))
|                |
|                |       E3
|                |     --------
|                |<----| n: 4 |
|                |     --------
|                |      (if (= n 1)
|                |      	n
|                |      	(* n (factorial (- n 1))))
|                |
|                |       E4
|                |     --------
|                |<----| n: 3 |
|                |     --------
|                |      (if (= n 1)
|                |      	n
|                |      	(* n (factorial (- n 1))))
|                |
|                |       E5
|                |     --------
|                |<----| n: 2 |
|                |     --------
|                |      (if (= n 1)
|                |      	n
|                |      	(* n (factorial (- n 1))))
|                |
|                |       E6
|                |     --------
|                |<----| n: 1 |
|                |     --------
|                |      (if (= n 1)
|                |      	n
|                |      	(* n (factorial (- n 1))))
|                |
------------------

Iterative
---------------------------------
(define (factorial n)
  (fact-iter 1 1 n))

(define (fact-iter product counter max-count)
  (if (> counter max-count)
      product
      (fact-iter (* product counter) (+ counter 1) max-count)))


 global env
------------------
|                |<--- env: global env
|                |     parameters: n
| factorial: --------> body: (fact-iter 1 1 n)
|                |
|                |
|                |<--- env: global env
|                |     parameters: product, counter, max-count
| fact-iter: --------> body:
|                |       (if (> counter max-count)
|                |           product
|                |           (fact-iter (* product counter) (+ counter 1) max-count))
|                |
|                |       E1 (factorial 6)
|                |     --------
|                |<----| n: 6 |
|                |     --------
|                |      (fact-iter 1 1 n)
|                |
|                |       E2
|                |     ----------------
|                |<----| product: 1   |
|                |     | counter: 1   |
|                |     | max-count: 6 |
|                |     ----------------
|                |      (if (> counter max-count)
|                |          product
|                |          (fact-iter (* product counter) (+ counter 1) max-count))
|                |
|                |       E3
|                |     ----------------
|                |<----| product: 1   |
|                |     | counter: 2   |
|                |     | max-count: 6 |
|                |     ----------------
|                |      (if (> counter max-count)
|                |          product
|                |          (fact-iter (* product counter) (+ counter 1) max-count))
|                |
|                |       E4
|                |     ----------------
|                |<----| product: 2   |
|                |     | counter: 3   |
|                |     | max-count: 6 |
|                |     ----------------
|                |      (if (> counter max-count)
|                |          product
|                |          (fact-iter (* product counter) (+ counter 1) max-count))
|                |
|                |       E5
|                |     ----------------
|                |<----| product: 6   |
|                |     | counter: 4   |
|                |     | max-count: 6 |
|                |     ----------------
|                |      (if (> counter max-count)
|                |          product
|                |          (fact-iter (* product counter) (+ counter 1) max-count))
|                |
|                |       E6
|                |     ----------------
|                |<----| product: 24  |
|                |     | counter: 5   |
|                |     | max-count: 6 |
|                |     ----------------
|                |      (if (> counter max-count)
|                |          product
|                |          (fact-iter (* product counter) (+ counter 1) max-count))
|                |
|                |       E7
|                |     ----------------
|                |<----| product: 120 |
|                |     | counter: 6   |
|                |     | max-count: 6 |
|                |     ----------------
|                |      (if (> counter max-count)
|                |          product
|                |          (fact-iter (* product counter) (+ counter 1) max-count))
|                |
|                |       E8
|                |     ----------------
|                |<----| product: 720 |
|                |     | counter: 7   |
|                |     | max-count: 6 |
|                |     ----------------
|                |      (if (> counter max-count)
|                |          product
|                |          (fact-iter (* product counter) (+ counter 1) max-count))
------------------