(1) Distance from Lot Lines to Structures.

(a) Every point on a structure shall be a minimum horizontal distance from every lot line which is not a street line equal to 3/4 (1/2 in "R-13") of the height of that point above the mean ground level at the base of said structure;

(b) Every point on a structure which faces a street shall be a minimum horizontal distance from the centerline of said street equal to 3/4 (1/2 in "R-13") of the height of that point above the mean ground level at the base of said structure;

(2) Spacing of Structures. The required minimum spacing shall be as follows:

(a) Between parallel structures (front-to-front, rear-to-rear, or front-to-rear), 50 feet for structures of 5 stories or less;

(b) Between obliquely aligned structures (front-to-front, rear-to-rear, or front-to-rear), the minimum distance required in the preceding sub-paragraph for structures of 5 stories or less may be decreased by as much as 10 feet at one end if increased by a similar or greater distance at the other end;

(c) Between the end walls of structures where said walls contain no legally required windows, 20 feet at any point. Where legally required windows occur in one or both end walls of structures, and such walls face each other, this distance shall be 30 feet for one-story and two-story structures, 35 feet for three-story structures, 40 feet for four-story structures, and 45 feet for five-story structures;

(d) Between the end walls of a structure and the front or rear walls of another structure, or between the side walls of separate structures, 30 feet at any point for one-story and two-story structures, 35 feet for three-story structures, 40 feet for four-story structures, and 45 feet for five-story structures;

(e) Between corners of adjacent structures that do not face each other or overlap, 20 feet at any point;

(f) Spacing between all parts of structures of 6 stories or more shall be determined by the following requirements:

(.1) The measurements in this section shall be made from the center of the proposed window sill of each of the lowest legally required windows in a structure which faces upon the wall of another structure on the same lot;

(.2) Using the center of said window sill as the centerpoint of an arc, there shall be projected from each window, on a horizontal plane perpendicular to the side of the structure, an arc extending 70 degrees on either side of the centerline of the window, where "centerline of the window" is defined as a line drawn from the center of said sill perpendicular to the side of the structure;

(.3) Said arc, projected as set forth in the above sub-paragraph, shall be divided into 28 sectors of 5 degrees for each sector;

(.4) The "Unregulated Area". In any combination of 14 of the 5 degree sectors, the walls of another structure on the same lot may be of any height or any distance from said window, subject only to the provisions of sub-paragraphs (c) and (e) above. This shall be known as the "unregulated area";

(.5) The "Regulated Area". In any combination of 14 of the 5 degree sectors, the distance from the wall containing the legally required window to any other wall shall be:

(.a) equal to the height of said other wall, minus

(.b) the height of said legally required window above average ground level;

(g) Spacing between structures of 5 stories or less and 6 stories or more shall be determined by computing the distance required for each type of structure (as herein set forth), and using the maximum requirement applicable.

(3) Courts. The minimum width of courts between wings of the same structure shall be determined by the following requirements:

(a) For buildings of 3 stories or less and not in excess of 35 feet high, the minimum width shall be not less than the length or depth of such court;

(b) For buildings over 3 stories or over 35 feet in height, the minimum width shall be not less than the length or depth of such court plus one-third of that portion of the height of the building over 3 stories or 35 feet.