Abstract: Masonry blocks conveyed in side-facing-side relation toward a cubing station for assembling into multi-tiered stacks are fed to a prepositioning station where the blocks are separated into groups of three and the trailing two blocks in each group are reoriented 90.degree. into a so-called tie pattern with the other block. The two trailing blocks remain in parallel relation and extend lengthwisely in the direction of conveyance. The tie-patterned groupings are fed to a patterning station where they are relatively repositioned as necessary into the arrangement predetermined by the particular tier pattern being assembled. Once properly oriented, the block groups are transferred to the cubing station.