Did you ever play The Prisoner? Where you go to the psychiatrist and he asks you all these questions, then the BASIC program crashes and prints an error message like "SYNTAX ERROR IN LINE ####" and beeps, leaving you at the "]" prompt?
But it's really an AppleSoft Basic Prompt Simulation to see how you will deal with the program crashing, judging you on if you go "CONT" or "NEW" or "RUN" or "CATALOG" or "LIST ####"!
What I didn't realize until I just looked it up now:
>In Prisoner 2 (the 1982 remake of the original), the game intentionally simulates a crash by showing a “Syntax error in line ###” message where the line number is actually your secret resignation code. The idea is that you might try to inspect or debug that line and type in the code, thereby revealing it — which is a loss condition because the game’s entire goal is to not give that number up.