The Four Wall paddleball court is 40 feet long, 20 feet wide with front and side walls 20 feet high, a back wall at least 12 feet high and a ceiling. A line midway between and parallel with the front and back walls divides the court in the center and is called the short line. A line five feet in front of the short line and parallel to it is called the service line. the area between the service line and the short line is called the service zone. A line 18 inches from and parallel with the side wall at each end of the service zone is called the service box. Vertical lines 3 inches from the floor, marked on each side wall, five feet back of the short line are called receiving lines. All lines are 1-1/2 inches wide and are an appropriate distinguishing color.