Wondering what tetrapods is wow then in Greek this means four legged If you observe you will see four legs protruding from a middle structure just like a star fish. This pods are nothing but concrete structures used to prevent coastal erosion. The name is so famous that now even the three-legged structures are also known as tetrapods.
They are designed in a way that they remove the force of coming waves by making the water flow around instead of against them. They also reduce displacement by allowing the random distribution of this pods as I call it to mutually join themselves or interlock.
Due to their design and how they weigh, thus pods can remain unshaken even under the most harsh weather conditions. A number of this pods arranged together will form a very strong interlocking, porous barrier that stabilizes the power of currents and wave