Distance between structures. Mobile homes and structures, buildings or roofed areas attached thereto, shall be separated from each other, and from other buildings and structures, other than accessory buildings and structures, at their closest points by a minimum of 20 feet, provided, however, that whenever two mobile homes have their longer sides parallel or essentially parallel to each other for more than 25% of the length of either, the minimum distance between the two mobile homes shall be 30 feet. The sides shall be considered essentially parallel if they form an angle of less than 45° when extended to intersect.