abstract
background
barb
barbed
barbwire
barrier
base
border
boundary
camp
close
closeup
crime
danger
defend
defense
fence
forbidden
freedom
guard
industrial
iron
isolated
limit
line
metal
military
old
pattern
prison
private
prohibit
property
protect
protection
razor
rust
rusty
safety
security
sharp
steel
symbol
trespassing
up
war
white
wire