abstract grayscale greyscale iron line metal rail rails railway railway line railways sleeper sleepers train trains transport air contour line glass linear measure tinker tool tools water brown free material texture wood wood stain ba1969 border chain links row architecture big building conduit electronics exhaust factory hydraulic line industrial industry large metallic pipe pipeline pipework piping shining silver technology tube tubes tubing backdrop background element gray grid grids lines pattern art building material composite material concrete facade Material property clouds coast coastline coruna EU.Coruña fence ocean sea sky Spain walk bolt corroded corrosion engineering grunge grungy old plate rivet rust series chain link fence fence line fence post gate gaurd impound pole secure security yard