For corner lots
M1 M2 M3
In all districts, as indicated, no primary business entrance, show window or sign shall be located on that portion of the street frontage of a corner lot within 75 feet of frontage on the same side of the street in a Residence District.
However, primary business entrances, show windows, or signs may be located on frontage less than 75 feet, but not less than 20 feet, from a Residence District boundary:
(a) if the total length of the block face containing such frontage is less than 220 feet; or
(b) if such frontage adjoins frontage on a corner lot in a Residence District; or
(c) if such frontage is separated from frontage in the Residence District by one or more zoning lots with single frontage.