英文關鍵字
danger
prison
protection
sky
security
military
barrier
border
fence
steel
barbed
metal
wire
war
background
boundary
iron
sharp
texture
abstract
barb
freedom
defense
barbwire
forbidden
wall
crime
guard
blue
safety
jail
camp
razor
surveillance
clouds
escape
line
concept
control
dangerous
prisoner
private
protect
symbol
warning
barbedwire
contour
global