aggregate pattern concrete concrete pattern concrete surface exposed aggregate gravel gravel exposed mpoukamvília patter red flower surface with patterns abstract background city color colored concrete colors crackles decay crack grunge grungy pattern patterns texture textures urban urban decay carpenter concrete material concrete texture construction metal nails nails nails on floor nails on slab shadow platform scaffolding wood deck wood grain wooden wooden deck close-up cobblestones sidewalk build lastrico terazzo abstract design concrete background design patterns gray stone urban texture