The court apron is similar to the basketball_court_apron() in that it is the area outside the court. It may be the same color as the interior of the court, but isn't necessarily. Unlike basketball_court_apron() however, the boundary line thickness doesn't matter since the lines are considered in-play and therefore are included in the court's length and width. This is a colored area inside of the free zone (see volleyball_free_zone()).
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