Also called Opus Reticulatum, a type of facing used on ancient Roman concrete or mortared rubbled walls. Reticulated work began to appear during the late Roman Republic and became widespread by the reign of Augustus. Prior to this, most facing used an irregular patchwork called opus incertum. Reticulated work looks like a diagonal checkerboard with its square stones set in a lozenge fashion, separated by fine joints. The stones are about 10 cm square and extend into the wall for 20 to 25 cm. The name is derived from the Latin rete, "net," because the wall surface has the appearance of a fishing net.
Examples of this style of facing may be seen at Ostia, in the Piazzale of the Corporations where tufa reticulate masonry forms the wall of a Roman guild office; on the terraces of the country villa built by Herod the Great at Jericho, Jordan; and at Rome in the wall of the Mausoleum of Augustus. Reticulated work was replaced by a type of brick wall-facing called opus testaceum, which became the most common method in the imperial era.