Two bar magnets lie end to end with unlike poles facing. Both magnets are turned end for end without changing the gap. One magnet is then turned end for end again. What happens after each stage?
After both turn, they repel; after one turns again, they repel.
After both turn, they repel; after one turns again, they attract.
After both turn, they attract; after one turns again, they attract.
After both turn, they attract; after one turns again, they repel.