advice alert appropriate behavior appropriate behaviour avoid black care concern danger dangerous denied directions not allowed not permitted permission denied polluted pollution prohibited prohibition protect protection red rules safety sign signs toxic toxicity warning warning sign water pollution water toxicity weathered white worn caution cutout emergencies emergency floor information isolated pictogram slip slippery slippery floor slippery surface slipping warn water wet wet floor wet surface yellow announcement appropriate-behavior appropriate-behaviour be-careful beware careful communicating communication informing Look looking lookout observant risk risks slow slow-down traffic vehicles warning-sign watch watch-out chock current electric electrical fence high installation net power station sundtech volt voltage chinese dangers english no diving rain rain-drops swimmers swimming ampelmännchen berlin don't-walk pedestrian pedestrians stop street traffic-light aged aging crossing elderly old risky road-sign security seniors signage speed-reduction street-sign symbol traffic-flow walk walkers walking consumption faucet health listen tap undrinkable unhealthy rail railway railway-station railway-tracks trains grunge isolated on white ruined steam train train triangle cautious direction inform message not-allowed not-permitted permission-denied please polite prohibitions rectangle rectangular text words