(under subclass 28) Preformed, or selected, element layer structure wherein the stratum is made up primarily of a plurality of nonuniform cuboid-like members, e.g., natural field stones.
(1) Note. Generally, the nonuniform members for this subclass where arranged in close rank and file still leave significant voids while the blocks of subclass 29 can be arranged, though not necessarily, to virtually eliminate such voids.
