$ clisp

<...snip...>

[1]> (load "quarto.l")
;; Loading file quarto.l ...
;; Loaded file quarto.l
T
[2]> (task15--color-predicates-demo)
*BBHS* is BLUE: T
*BBHS* is RED:  NIL
*SRSC* is BLUE: NIL
*SRSC* is RED:  T
NIL
[3]> (bye)
Bye.