I had a lit professor once who would do oral quizzes on the reading but anyone with half a brain could get literally 140% on them without doing the reading since he’d also give extra credit questions.
The first time through the quiz one day, he asked something like “Who killed Achilles? A: Paris. B: London. C: Berlin.” Then later, when repeating the question, he said “A: Paris. B: Berlin. C: London.” Process of elimination.
I’m not even kidding about the city names.
On top of that, even if he didn’t give it away in the question, you just had to wait until he read off an answer and suddenly the entire class started writing. Dead giveaway.
Fun fact (because there’s nothing more fun than technicality!): Technically it wasn’t his life’s work. Well before his work on nuclear fission, Oppenheimer was actually responsible for originally theorizing the existence of both antimatter and black holes. He was a more intuitive physicist than a technical one, so he didn’t follow through on these ideas, instead letting others carry the work forward.