Reminds me of my first job at a world leading RnD organisation when I took the test code that the lead engineer on a fluids mixing project had written and added some sensible prompts.

His original Code was cli program who's sole prompt was ?

You had to enter integers , 1, 2 3 etc to select the next option - the possibilities for errors where immense - by this time we had scaled to 1:1 tests where the chemicals for a run could cots over 10K£ per run