Explain fair is foul and foul is fair?

Answer 1

The "foul pole," those tall yellow poles on the outfield walls that mark the foul lines vertically, are actually in fair territory. So if a long fly ball strikes a foul pole, it's a fair ball (and a home run!)

Answer 2

This is a line from Macbeth, and I don't understand Shakespeare anyway. Apparently it means something like you can't judge a book by its cover, and what may seem ugly and unpleasant may really be good and wholesome, and vice versa.

Answer 3

This rule describes when the Baseball strikes the foul pole. Despite being called the foul pole, the ball is always fair, if it hits the foul pole.