"Ahu" are stone platforms on which many moai sit. There are 313 known ahu and 125 of these carry moai. The biggest, Ahu Tongariki is 220 m (720 ft), and had the most (15) and tallest moai.
No architect troubled to design houses that suited people who were to live in them, because that would have meant building a whole range of different houses. It was far cheaper and, above all, timesaving to make them identical.
