Teams can be of 1 or more players. Each team has a pitcher and possibly one or more fielders. The playing field is composed of a wall and the area in front of it. A strike zone based on a baseball/softball strike zone is drawn on a wall. The pitcher pitches a tennis ball from a set distance depending on the age of the players. If the batter swings and misses it is a strike. If the ball hits the wall within the box, it is a strike. Three strikes is an out; four balls is a walk. A fair or foul area is defined at the beginning of the game. A ball must travel a minimum distance in the air to be declared a fair ball. Increasing distances of carry in the air are used to decide whether a hit is a single, double, triple or home run. The team with the most runs at the end of the game wins.
Contributed by Keith - Thank you!