Wall - just about anything that suggests a wall in structure or operate or impact; "a wall of drinking water"; "a wall of smoke"; "a wall of prejudice"; "negotiations bumped into a brick wall" However only initially intended as a way of comprehension a selected set of artists, Greenberg's definition https://elliotzhnsw.iamthewiki.com/7981564/the_single_best_strategy_to_use_for_art