In bedrooms with a mosaic floor the place for the bed is ordinarily white, being separated from the rest of the room by a stripe suggestive of a threshold. A similar division is often indicated in the wall decoration, particularly that of the second style; the part designated for the bed is set off by pilasters on the end walls, and differently treated both in respect to the decorative design and in the arrangement of colors. [Illustration: Fig. 122.--End of a bedroom in the house of the Centaur, decorated in the first style. At the left, alcove for the bed; above, two windows.] VIII. DINING ROOMS As long as it was customary to sit at meals any fair-sized apartment could be used as a dining room. When the early Italic house was extended by the addition of a peristyle, and the Greek custom of reclining at table was introduced, it became necessary to provide a special apartment, and the Greek name for such a room with the three couches, _triclinium_, came into use. For convenience in serving, the length of a dining room, according to Vitruvius, should be twice the width. At Pompeii, however, the dimensions are less generous; with an average width of 12 or 13 feet the length rarely exceeds 20 feet. In many cases one end of the room opened on the peristyle, but could be closed by means of broad doors or shutters. [Illustration: Fig. 123.--Plan of a dining room with three couches. A. Upper couch, _lectus summus_. B. Middle couch, _lectus medius_. C. Lower couch, _lectus imus_. D. Table, _mensa_.] The plan of a typical dining room is given in Fig. 123. The couch at the right of the table was called the upper couch; that at the left, the lower; and that between, the middle couch. With few exceptions each couch was made to accommodate three persons; the diner rested on his left arm on a cushion at the side nearer the table, and stretched his feet out toward the right. Hence, the first on the upper couch had what was called 'the highest place.' The one next was said to recline 'below' him, because lying on the side toward which the first person extended his feet; the man at the outer end of the lower couch was said to be 'at the foot,' _imus_. When in the Gospel of John we read of a disciple "lying on Jesus' breast," the meaning is easily explained by reference to Roman usage; John was reclining in the place next below the Master. This arrangement makes clear to us the reason why the couches were so placed that the lower one projected further beyond the table than the upper one; the feet of those on the lower couch were extended toward the end furthest from the table.