The rules for doubles are the same as singles, except the
wider court is used.
Players within a pair do not have to hit alternate shots,
any player can hit the ball.
However, the serve rotates so that each player serves once
every fourth game.
For instance from Player A in Pair A, to Player B in pair B,
back to Player C in Pair A and then to Player D in Pair B.
Players can only change the order of serving and receiving
at the end of a set.
The server's partner and the receiver's partner may stand
anywhere they like on the court during the serve, even if it obstructs play.
Traditionally however, each player takes one side of the
court.