The Romans required some of their furniture for out-door use. Besides the curule chairs and lofty seats which were carried into theatres or baths, and other places of public resort, they used litters. The sofas or couches were sometimes carried on the necks of six or more slaves, and served as litters. But special contrivances like the Indian palanquins were made with or hung under poles, with curtains or shutters. Stations of such conveyances for public use were established in Rome. The subjects of the carving and ornamentation of Roman furniture were the classic legends mainly derived from the Greek mythology. Roman house walls were, however, in later years profusely decorated with conventional representations of architecture, and panels richly coloured on which were painted figures of dancers, cupids, gods and heroes; sometimes commonplace landscapes and domestic scenes. Their solid furniture was decorated with masks, heads of heroes, legs and feet of animals, and foliage, generally the leaves of the acanthus, of an architectonic kind. The great achievement of the Romans in woodwork of a constructive kind was the machinery contrived for public shows, such as the cages shot up out of the sand of the arena of amphitheatres, of which the sides fell down, leaving at liberty the beasts wanted for fights or for the execution of criminals. Of such constructions probably nothing in the middle ages, when timber abounded and the use of it was thoroughly understood, exceeds the following; a description by Pliny of a device of C. Curio, in Africa, when celebrating the funeral games in honour of his father:-- "He caused to be erected close together two theatres of very large dimensions and built of wood, each of them nicely poised, and turning on a pivot. Before mid-day a spectacle of games was exhibited in each, the theatres being turned back to back, in order that the noise of neither of them might interfere with what was going on in the other. Then, in the latter part of the day, all on a sudden, the two theatres were swung round and, the corners uniting, brought face to face; the outer frames too were removed (_i.e._ the backs of each hemicycle) and thus an amphitheatre was formed, in which combats of gladiators were presented to the view; men whose safety was almost less compromised than that of the Roman people in allowing itself to be thus whirled round from side to side." The following woods were in use amongst the Romans:--