Wave-dissipating concrete block
A wave-dissipating concrete block is a naturally or manually interlocking concrete structure designed and employed to minimize the effects of wave action upon shores and shoreline structures, such as quays and jetties.
One of the earliest designs is the Tetrapod, invented in 1950. Other proprietary designs include the Modified Cube, the Stabit, the Akmon, the Dolos, the , the Seabee, the Accropode, the Hollow Cube, the A-jack, the Xbloc and KOLOS among others.