retaining wall detail. closeup of dry stone wall built with natural flagstones and wallstones of irregular s and sizes

abstract ancient architectural architecture backdrop background barrier black block blue brick build building built cement close closeup concrete construction countryside craftsmanship dark design detail dry exterior flagstones flat garden grey house irregular limestone masonry material modern natural nature old outdoor pattern perspective retaining rock rural shapes sizes stone stonework structure style texture traditional vintage wall wallpaper wallstone wallstones