Racket version (should work in most Scheme implementation too actually): (let loop () (display (list-ref '("╱" "╲") (random 2))) (loop)) Use `racket -e <e

Racket version (should work in most Scheme implementation too actually): (let loop () (display (list-ref '("╱" "╲") (random 2))) (loop)) Use `racket -e <expr>` tu run it directly, for Guile it should work with `guile -c <expr>` but it seems that the unicode charaters make it crash (however it works if you copy the line of code in Guile's REPL rather than on the command line with -c).