abstract
arrest
background
barbed
barbwire
barrier
border
boundary
danger
dangerous
design
deterrent
fence
freedom
gate
grunge
guard
iron
isolated
isolation
jail
keep
metal
old
outdoors
pattern
pole
post
prevent
prison
protect
protection
rust
rusty
safety
sea
secure
security
shape
sharp
shore
sky
spike
steel
sting
torture
trespass
war
water
wire