Hellenistic and Graeco-Roman forms are more conventional, and the new motives that belong to these periods are mostly floral. Busts and masks are the usual handle-plaques and spouts; heads and limbs of various animals are allotted certain decorative functions, as for instance the spirited mules' heads mentioned by Juvenal, which formed the elbow-rests of dining couches. These structural pieces are frequently inlaid with silver and niello. Bronze chairs and tables were commonly used in Hellenistic and Roman houses, and largely took the place of monumental vases that were popular in earlier days. Small household articles, such as lamps, when made of bronze are usually Roman, and a peculiarly Roman class of personal ornaments is a large bronze brooch inlaid with coloured enamels, a technique which seems to have had a Gaulish origin.