atom atomic character color colour danger nuclear pictogram radiance radiancy radiation radio-activity security shape sign symbol uranium advice alert announcement appropriate-behavior appropriate-behaviour aware awareness black care careful caution communicating communication considerate consideration directions fence informing lettering letters red signs warning white wording words ban beware camp-fire embargo fire flame inhibition injunction interdict oval prohibition proscription round sphere suppression access-denied advising apology avoid behavior behaviour communicate concern construction construction-site dangerous entry-denied entry-prohibited inconvenience inconvenient information no-access no-entry not-allowed not-permitted permission-denied prohibited restricted restriction restrictions risk risks risky safety warning-sign yellow cold flood lightning nature rain storm road snow square street thunderbolt travel water wet wild cloud downpour drop droplet barred bars control do not do not enter forbidden impede locked notice pipes posted prevent prevented Restrict blue bright local public-area reptiles seen sighting sightings snakes venomous handrails high metal metallic mobile non-slip patterned rails ribbed silvery stairs steps birds blue sky protection road crossing water birds water fowl wildlife footpath forest keep out private public right of way tree trees trespass trespassing walk wood