All Hohokam houses were earth lodges with much the same general plan. They were single-unit structures, usually with depressed floors. Entrance was through a covered passage or vestibule, normally in the middle of one side. Walls were constructed of poles, brush, and mud. The roofs, which consisted of rafters overlaid by smaller timbers, were supported by upright posts set in the floor. During Pioneer times houses were larger than in any other Hohokam period and in some cases were up to thirty-five feet square. Some archaeologists believe that the largest houses may have been occupied by more than one family.[31]^c Others feel that it is more probable that they were ceremonial structures.[30] During most of the time, four or five roof supports were employed, but there was one phase early in the period when a great many posts set in rows were used and it is hard to see how such a house could have been lived in at all. So much skill was required to erect these houses that they certainly must not represent the people’s first attempt at housebuilding, and there was undoubtedly an earlier phase for which evidence has not yet been found. No material has been found which may be attributed to a pre-ceramic period, unless the Cochise culture proves to be ancestral to the Hohokam. Pottery is found in even the earliest Pioneer levels. The Hohokam did not have any corrugated pottery. All their wares were smooth and were produced by the paddle-and-anvil technique. When this method is used to shape and finish a piece of pottery, a round or mushroom-shaped object, known as an anvil, is held inside the vessel to receive the force of the blow, while the exterior is struck with a wooden paddle. Air was permitted to flow over the pottery while it was being fired, producing an oxidizing atmosphere. There are important differences between the pottery making methods of the Hohokam and those of the Anasazi. As has been previously noted, among the Anasazi, the final step in the finishing process was to shape and smooth the vessel through scraping with a gourd or pottery spoon, and most pottery was fired in a reducing atmosphere.