The County Department of Public Works is hereby authorized, empowered and directed, pursuant to §
C8-2X of the Suffolk County Charter, to erect signs on the grounds of the Armed Forces Plaza and the Dennison Building stating that roller-blading, roller-skating and skateboarding are prohibited anywhere on the grounds of the Armed Forces Plaza and the Dennison Building, said signs to be conspicuously visible with the lettering to be at least six inches in height and concluding with "UNDER PENALTY OF LAW."