Why do flat drain covers clog so easily during heavy rain? You build two wire-mesh covers for the same drain hole: one flat and one shaped like a dome over a small bowl. You set up a tilted gutter and pour pails of water mixed with four types of debris: - Dried leaves - Grass - Soil - Plastic wrappers For each type you check whether the cover clogs or lets water pass. Compare the results to see which shape keeps the drain clear.