A story told from an old school Russian professor about physics at the university of Moscow under Stalin:

It’s exam. The professor enters the room and tells students there will be 3 exams.

One extremely hard all books allowed, it’s either pass with top grade or fail, nothing in between.

One hard, one book allowed, it’s either pass with moderate grade or fail, nothing in between.

One moderate, no book allowed, but if you know the books you can pass, it’s passing grade or fail.

Students are told to sort according to the exam they want to take. Very hard to the right, hard in the middle, moderate to the left.

Once students are sorted the professor says: „ Right pass. Middle come back next year. Left go home, Russia does not need you.“