CL-USER> (visualize '(a b c ((d (e ((() ()))) f)) (g)))
A
|
B
|
C
|
+---+
|   |
|   +---+
|       |
|       D
|       |
|       +---+
|       |   |
|       |   E
|       |   |
|       |   +---+
|       |       |
|       |       +---+
|       |           |
|       |           +---+
|       |           |
|       |           +---+
|       |
|       F
|
+---+
    |
    G

NIL