This document discusses various signs and notices that provide rules and information. It explains that signs prohibiting smoking can be found in hospitals and stores to mark sterile areas, and no parking signs can be found near traffic lights or in non-parking areas. Turning phones off is required in places like gas stations to prevent explosions, and libraries and classrooms require silence. Other signs address not eating in laboratories, feeding animals in zoos, danger areas, smoking areas, litter, and restricted access. The signs are meant to communicate important safety rules and regulations to the public in different settings.