The Staircase Grading Method

I am completely convinced my engineering professor grades papers by throwing them down a staircase and giving the highest marks to whichever ones land furthest. I wrote exactly the same answer as my friend for a 15-mark midterm question—literally identical because we memorized the same notes—and I got a 12 while he got a 4. Neither of us has the courage to go for the paper-showing session because we know the professor will just get offended and deduct marks from both of us for questioning his 'academic judgment.