 The styles of grills used are as varied as the methods of producing them; some are homemade while others are custom made.In a Hawaii-style pig roast, a large pit is typically dug into the ground and lined with banana leaves, as lava rocks are heated over an open flame until they are very hot.The heated rocks are placed into the pit, and a seasoned pig is placed inside and covered with additional banana leaves, which serve as insulation and for flavor.