One characteristic which typifies Jefferson 's architecture is the use of the octagon and octagonal forms in his designs. Palladio never used octagons, but Jefferson employed them as a design motif—halving them, elongating them, and employing them in whole as with the dome of Monticello, or the entire house at Poplar Forest. The Roman Classical Revival style and later the Greek Revival style emulated the form of classical Roman and Greek temples. The Greek Revival style has much in common with the Roman Classical Revival style in its reliance on the temple form, front pediment, and classical order columns. A typical Roman Classical Revival style building in Pennsylvania would have a front facade dominated by a full height columned portico topped