alloy
aluminum
architecture
background
black
board
border
construction
design
fence
frame
gray
grid
grunge
hard
heavy
industrial
industry
iron
ironworks
line
material
mesh
metal
metallic
old
page
panel
pattern
plaque
plate
polished
rust
rusty
shape
sheet
shiny
sign
silver
space
stainless
steel
surface
template
texture
textured
tin
tough
vintage
wall