Hill, 482 U.S. 451, 107 S.Ct. 312, 332, 108 S.Ct. 112, 92 S.Ct. at 2304 (locating that an anti-sound ordinance was not obscure exactly where it was composed particularly to forbid disturbance of schools simply because "prohibited disturbances are conveniently measured by their effect on standard functions of the school"). 41, 119 S.Ct. 1849, one hundred forty four L.Ed.