Abstract: Interlocking stackable block structures for use in erecting a shock-resistant wall array and including block structures in both fence block and post block configurations. The top surface of each of the blocks has a pair of parallelly disposed upwardly protruding laterally extending ridge projections which mate and interlock with projections formed on the bottom surface of the block. The block configuration is further provided with cores for drainage and load reduction purposes, but the upper and lower mating faces of the block have a load-bearing web which supports a superimposed stacked block thereon. The cores of the post block contain a reinforcing rod held in grout so as to provide strength and stability. Also, the post block structures are provided with recesses for lockingly receiving fence block therein, thereby providing an arrangement where the fence block array floats within the recesses and is thereby provided with a greater degree of stability.