Teaching table tennis to a tennis player
I've always found it interesting, even fascinating, to coach table tennis to a tennis player. I've had many tennis players as students over the years. I also play tennis at a 4.0 level (that's like 1800 in table tennis), but with an extremely lopsided forehand-oriented game. But that's true of most table tennis players - the first time we play tennis, we have nice forehands, but find the backhand somewhat awkward.
Yesterday I coached a 6'5" former 5.5 (that's like 2100-2200) tennis player. He'd never had lessons before, and had only been a "basement" player. He very quickly picked up the forehand, and after five minutes, was pounding forehands. He also quickly picked up on the backhand, but did so in a very backhand stance (like tennis), and basically played an aggressive blocking backhand from a bit off the table. Near the end of the session we did a drill where I looped my forehand rather aggressively to his backhand, and though it was the first time he'd ever done this, he was able to block them back very consistently, though he took the ball a couple steps off the table rather than off the bounce, as you are "supposed" to do when blocking. But the blocks were surprisingly effective, as he kept them rather low. (It did leave him open on the wide forehand, and I don't think he has a counterloop yet!)
Because of his tennis skills, he quickly picked up just about every aspect, could even loop backspin after a few tries. He had great difficulty in reading my serves, but without any coaching, quickly figured out how to push my backspin serve back, i.e. did a tennis "slice." He also learned to serve with backspin pretty quickly, though he wasn't able to get a good sidespin. A few times when I went to his forehand, he did a highly professional-looking running forehand.