tetrapod
A concrete wave breaker, shaped like a huge caltrop or jack. The edges are typically rounded, but don't have to be. They're placed in large numbers at the edges of harbors or beaches, acting as a reef.
A concrete wave breaker, shaped like a huge caltrop or jack. The edges are typically rounded, but don't have to be. They're placed in large numbers at the edges of harbors or beaches, acting as a reef.
