chain link fence fence fence line fence post gate gaurd impound iron metal pole rail secure security yard bar bars detail details fenced grating grille metallic safe wire wire-fenced barrier bolted crash-barrier curve curved fencing grass grassed protection protective safety secured solid strength strong trees barbed wire barbs barricade danger double gray grey razor wire restraint security fence sharp silvery spirals strands twists angle angles appearance deteriorating light old protect rust rusting rusty security-fence texture textures barbed-tape barbed-wire injury razor-sharp razor-wire warning forbidden free freedom prison railing sky trapped