The park shall be generally planned around one or more central greens or quadrangle areas, with consideration given to the relationship of various buildings and uses to each other. However, such greens or quadrangle areas may be located at the edge of a proposed business park in order to facilitate greater coordination with any neighboring public recreation area or land protected by a conservation easement. A minimum of 10% of the total planned business park area shall be devoted to such greens or common passive recreational areas. This shall be in addition to any normal required yard and setback areas or limitations upon coverage. The purpose of this is to create a stronger sense of place, and facilitate interaction among the employees, customers and residents of mixed use areas. Examples of such green or quadrangle areas may include town squares, assembly areas, and smaller landscaped or mowed areas with amenities, such as benches, lighting, public art and fountains. At least 75% of areas proposed for central greens or quadrangle areas shall be free of wetland or slope areas of greater than 5%. These areas may be privately owned, or owned and managed by a tenant or owners' association, provided there is a reasonable degree of access by residents, employees, and customers.