An improved corbel includes a first tier having first blocks and a second tier having second blocks. Each of the first blocks includes a first aperture extending through the block from a first surface to a back surface and a second aperture formed through a top surface of the block, extending into the first aperture. The first blocks are arranged on a substantially planar surface to align the respective first apertures to define a first passageway. Each of the second blocks includes a third aperture extending through the second block from a top surface to a bottom surface. The second blocks are disposed above the first tier to align the third aperture of each of the second blocks with the second aperture of the first blocks to form a second passageway.