1, 250, 623. Blocks for breakwaters &c. MITSUI REAL ESTATE CO. Ltd. and T. AKAMATSU. 22 July, 1968, No. 34958/68. Heading E1H. A breakwater &c is protected from erosion by at least one layer of blocks 1 each comprising three integral pillar members 2, 3, 4 of the same dimensions and cross-section (which may be square, circular, polygonal &c) the pillar members each being disposed transversely (e.g. normally) to the other two members so that both ends (which may be flat, domed or pointed) extend an equal amount beyond the other members. The pillar members 2, 3, 4 may have a length to width or diameter ratio of 4 : 1. The blocks 1 may be oriented with respect to the surface they protect either as shown in Fig. 1 on surface 14 or as shown in Fig. 5 on surface 17.