(a) No person shall use the public streets or sidewalks for any purpose which would cause large crowds to gather, thus obstructing the free use of such streets or sidewalks.
(b) No person shall collect or stand in a crowd, or arrange, encourage or abet the collection of other persons in crowds, for illegal or mischievous purposes in any public place.
(c) No person shall jostle or roughly crowd persons in any street, alley, park or public building.