When I used to use the traditional classroom for PADI OW rather than eLearning, I always made a point to show students a DIN connection during review of Knowledge Reviews before getting to the quizzes and tests. Otherwise, very high rate of incorrect answers on that one question. Seems no one really picks up on the DIN versus yoke when doing the coursework. So now I show a DIN during the first hands-on gear assembly, since I figure eLearning didn't register with them any better than the book & video.