Factorial in lisp recursive process

factorial-recursive.lisp

(defun fact(n)
  (if (<= n 1)
      1
      (* n (fact (- n 1)))))
SICP3> (fact 10)
  0: (FACT 10)
    1: (FACT 9)
      2: (FACT 8)
        3: (FACT 7)
          4: (FACT 6)
            5: (FACT 5)
              6: (FACT 4)
                7: (FACT 3)
                  8: (FACT 2)
                    9: (FACT 1)
                    9: FACT returned 1
                  8: FACT returned 2
                7: FACT returned 6
              6: FACT returned 24
            5: FACT returned 120
          4: FACT returned 720
        3: FACT returned 5040
      2: FACT returned 40320
    1: FACT returned 362880
  0: FACT returned 3628800