機器
ammo
army
assault
automatic
automatic rifle
barrel
blackboard
blank
board
caliber
chalk
chalkboard
class
danger
design
device
draw
drawn
education
handwriting
image
iron
isolated
lesson
line
lineart
lithography
mechanical
metal
military
old
oldfashioned
retro
school
selfloading
shot
sketch
special
steel
technology
texture
threaded
trigger
war
weapon
weapons
white
write