background construction diamond element grating gray grille metal metallic rack rhombus saavem texture frame green path route stone track walk walking walkway way cracked crystalline granitic grey hard natural nature rock rough brick broken cement concrete grey.gray grunge render wall 3D abstract architecture effect elements floor geometry parallelogram tile visual backdrop blue brown decay detail ol rust rusty silver urban black design grungy. city pattern pavement cornwall England layer line lines slate white light rounded shadow solid spherical spheroid spheroidal