機器
abandoned
ancient
antique
appliance
architecture
background
barrel
black
corrosion
course
device
drive
engineering
equipment
gear
gearing
grunge
infrastructure
installation
iron
lock
machinery
mechanics
mechanism
metal
mill
motor
movement
natural
nature
old
process
retro
rotating
round
rusty
setting
steel
stroke
technology
teeth
tool
transmission
vintage
water
wheel
white
work