英文關鍵字
barbed
wire
fence
barb
chain
link
gaol
security
grid
clouds
low
angle
tape
time
lapse
metal
danger
protection
sharp
steel
prison
barrier
blue
sky
razor
freedom
points
boundary
iron
obstacle
territory
zone
defense
concept
military
bondage
movement
guard
white
background
forbidden
safety
outdoors