How to overcome nature's desire to topple your wall The probIem is a familiar one to most builders and designers. The ground surface at one location has to he higher (or lower) than at some nearby point. There isn't enough horizontal distance between those two points to drop the grade with a conventional 1:2 slope-or flatter if it's to be a mowable lawn-so the solution is some type of a retaining structure. Numerous choices are available. They range in complexity from simple gravity structures that rely on their own dead weight to ...