boat choppy concept danger folded ocean origami paper rough sea storm stormy vulnerable water waves white atlantic islands islets lane marker norway Sea lane sign tower warning beware bus car drive road safety security street traffic transportation travel vehicle yellow animal black cat civilisation nature shape square wild dog elephant burn burning conceptual fire light lighting macro match object phosphorus saavem background diamond plate diamondplate grunge grungy metal Portland steel stripes texture warn wear worn access-limited advice advising alert appropriate-behavior appropriate-behaviour authorised-entry-only authorized-entry-only behave behavior behaviour care caution communicate communication concern confined-space dangerous information informing lettering limited-access limited-permission limited-space red restricted restriction restrictions risk risks risky signage unauthorised unauthorized warning-sign access-denied avoid communicating damage demolition denied destruction directions fence fencing keep-out mesh message no-access no-entry not-allowed not-permitted permission-denied prohibited prohibition unwanted warning sign weathered wire-mesh