"‘the Tetrapod like a three-dimensional Mercedes Benz sign’"
Tetrapod structures as a seawall defence
GNU Free Documentation LicenseTetrapod structures as a seawall defence - Credit: Magnus Manke

A Tetrapod is a four-legged concrete structure used within coastal defenses to reduce erosion by breaking the force of incoming waves. The interlocking shape of the Tetrapod structure has proved more stable than other barrier materials such as boulders and concrete blocks, which tend to become dislodged over time by the force of the ocean.