$ clisp

<...snip...>

[1]> (load "lsystem.l")
;; Loading file lsystem.l ...
;; Loaded file lsystem.l
T
[2]> (setf lsys (make-lsys '((a a b) (b a)) '(a)))
#<LSYS #x106AF795>
[3]> (visualize-lsys lsys)
Generation 0: (A)
NIL
[4]> (iterate-lsys lsys)
NIL
[5]> (visualize-lsys lsys)
Generation 1: (A B)
NIL
[6]> (iterate-lsys lsys)
NIL
[7]> (visualize-lsys lsys)
Generation 2: (A B A)
NIL
[8]> (iterate-lsys lsys)
NIL
[9]> (visualize-lsys lsys)
Generation 3: (A B A A B)
NIL
[10]> (iterate-lsys lsys)
NIL
[11]> (visualize-lsys lsys)
Generation 4: (A B A A B A B A)
NIL
[12]> (iterate-lsys lsys)
NIL
[13]> (visualize-lsys lsys)
Generation 5: (A B A A B A B A A B A A B)
NIL
[14]> (iterate-lsys lsys)
NIL
[15]> (visualize-lsys lsys)
Generation 6: (A B A A B A B A A B A A B A B A A B A B A)
NIL
[16]> (iterate-lsys lsys)
NIL
[17]> (visualize-lsys lsys)
Generation 7: (A B A A B A B A A B A A B A B A A B A B A A B A A B A B A A B A A B)
NIL
[18]> (iterate-lsys lsys)
NIL
[19]> (visualize-lsys lsys)
Generation 8:
(A B A A B A B A A B A A B A B A A B A B A A B A A B A B A A B A A B A B A A B
 A B A A B A A B A B A A B A B A)
NIL
[20]> (iterate-lsys lsys)
NIL
[21]> (visualize-lsys lsys)
Generation 9:
(A B A A B A B A A B A A B A B A A B A B A A B A A B A B A A B A A B A B A A B
 A B A A B A A B A B A A B A B A A B A A B A B A A B A A B A B A A B A B A A B
 A A B A B A A B A A B)
NIL
[22]> (bye)
Bye.