Height and Setbacks. The maximum height of the fence, wall, hedge or similar structure shall be determined by the setback distance between the front property line and the location of the fence, wall, hedge or similar structure. The maximum height of a fence, wall, hedge or similar structure with a front setback of less than two feet (2') shall be four feet (4'). The maximum height of a fence, wall, hedge or similar structure with a front setback of two feet (2'), but less than six feet (6'), shall be five feet (5'). Beginning with a six foot (6') front setback, the maximum height of the fence, wall, hedge or similar structure shall increase on an even gradient from a maximum of six feet (6')in height at foot front setback to seven feet (7') in height at a twenty foot (20') front setback. Decorative columns or posts may be allowed to exceed the height of the primary portion of the fence.