A block having a semicircular male lobe and a semicircular female recess on opposing sides thereof. On other opposing sides of the block, there is formed a side edge shape such that when neighboring blocks are placed together, a circuitous water channel is formed between the blocks. The block includes cable channels formed therethrough, with the cable channels opening at the side edges into cable cavities. The cable cavities facilitate access to ends of the cables when the blocks are placed side by side.