abstract
background
barb
barbed
barbwire
barricade
blue
border
boundary
camp
concrete
confined
crime
danger
defending
defense
fence
freedom
guard
human
hurdle
independence
iron
metal
military
no
old
outdoors
people
pole
post
prison
private
propriety
protection
razor
rebellion
refugee
rights
rusty
safety
security
sharp
sky
space
trapped
vertical
weathered
wire