agriculture
barb
barbed
barrier
blue
bob
bobbed
border
boundary
camp
captive
captivity
capture
captured
concentration
danger
ethnic
exile
farm
farming
fence
fencing
frontier
ghetto
iron
metallic
minority
oppression
people
prison
prisoner
protection
rebellion
refugee
rural
security
sharp
sign
sky
steel
submission
surrender
symbol
territory
torture
trench
vertical
victim
war
warfare
wire