$ clisp

<...snip...>

[1]> (load "quarto.l")
;; Loading file quarto.l ...
;;  Loading file lp.l ...
;;  Loaded file lp.l
;; Loaded file quarto.l
T
[2]> (task83--place-piece-demo)
Quarto board with pieces for ppd...
D    [B-] **** **** ****
C    **** [B+] **** ****
B    **** **** [b-] ****
A    **** **** **** [b+]
     1    2    3    4
(R-) [R-] (R+) [R+] (r-) [r-] (r+) [r+]
(B-) [B-] (B+) [B+] (b-) [b-] (b+) [b+]
On which cell will you place [R-], X?
(A1 A2 A3 B1 B2 B4 C1 C3 C4 D2 D3 D4)
> D4
X:  Placing piece [R-] on cell D4 ...
D    [B-] **** **** [R-]
C    **** [B+] **** ****
B    **** **** [b-] ****
A    **** **** **** [b+]
     1    2    3    4
(R-) (R+) [R+] (r-) [r-] (r+) [r+]
(B-) [B-] (B+) [B+] (b-) [b-] (b+) [b+]
On which cell will you place (R+), X?
(A1 A2 A3 B1 B2 B4 C1 C3 C4 D2 D3)
> A1
X:  Placing piece (R+) on cell A1 ...
D    [B-] **** **** [R-]
C    **** [B+] **** ****
B    **** **** [b-] ****
A    (R+) **** **** [b+]
     1    2    3    4
(R-) [R+] (r-) [r-] (r+) [r+]
(B-) [B-] (B+) [B+] (b-) [b-] (b+) [b+]
On which cell will you place [r-], X?
(A2 A3 B1 B2 B4 C1 C3 C4 D2 D3)
> C1
X:  Placing piece [r-] on cell C1 ...
D    [B-] **** **** [R-]
C    [r-] [B+] **** ****
B    **** **** [b-] ****
A    (R+) **** **** [b+]
     1    2    3    4
(R-) [R+] (r-) (r+) [r+]
(B-) [B-] (B+) [B+] (b-) [b-] (b+) [b+]
On which cell will you place (r-), X?
(A2 A3 B1 B2 B4 C3 C4 D2 D3)
> B3
That location cannot be chosen, please try again.
On which cell will you place (r-), X?
(A2 A3 B1 B2 B4 C3 C4 D2 D3)
> B1
X:  Placing piece (r-) on cell B1 ...
D    [B-] **** **** [R-]
C    [r-] [B+] **** ****
B    (r-) **** [b-] ****
A    (R+) **** **** [b+]
     1    2    3    4
(R-) [R+] (r+) [r+]
(B-) [B-] (B+) [B+] (b-) [b-] (b+) [b+]
On which cell will you place [b-], X?
(A2 A3 B2 B4 C3 C4 D2 D3)
> B3
That location cannot be chosen, please try again.
On which cell will you place [b-], X?
(A2 A3 B2 B4 C3 C4 D2 D3)
> B2
X:  Placing piece [b-] on cell B2 ...
D    [B-] **** **** [R-]
C    [r-] [B+] **** ****
B    (r-) [b-] [b-] ****
A    (R+) **** **** [b+]
     1    2    3    4
(R-) [R+] (r+) [r+]
(B-) [B-] (B+) [B+] (b-) (b+) [b+]
NIL
[3]> (bye)
Bye.