abstract
architecture
art
background
big
black
blue
chemical
construction
container
curve
depot
detail
diagonal
energy
factory
fuel
gas
gasoline
handrail
industrial
industry
ladder
lines
metal
oil
people
petrochemical
petrol
petroleum
plant
power
production
refinery
shadow
silo
sky
stair
staircase
stairs
stairway
steel
steps
storage
store
structure
tank
up
white
yellow