abstract aluminium aluminum backdrop background blue color coloration colors colour colours decorative distinctive ductile-metal impressions interconnected interlinked light metal metallic raised shaped shapes sheet shiny stippled style surface surfaced surfaces texture textured textures thick thin wallpaper cover iron non-skid oxide plate ridges rust San Francisco sidewalk urban aged burn damage damaged degraded grunge paint scar weathered decay design graffity grafitty graphic grungy urban decay blank copyspace corroded faded scratched sign yellow construction diamond element grating gray grille rack rhombus saavem clip art clipart gold illustration striped stripes scribbles impasto