機器
architecture
background
black
canal
circle
close
cogwheel
control
dam
design
dike
energy
engine
engineering
equipment
flood
floodgate
gate
gear
grunge
industrial
industry
iron
irrigation
large
lock
machinery
mechanical
mechanism
metal
nature
old
open
outdoor
power
retro
river
rust
rusty
sluice
steel
technology
toothed
transportation
valve
vintage
water
water flow
wheel