Prominent among the archaeological pieces are the moai that range in height from 2 m to 20 m and are for the most part carved from the yellow–brown lava tuff, using simple picks (toki) made from hard basalt and then lowered down the slopes into previously dug holes. There are many kinds of them and of different sizes: those in the process of being carved, those in the process of being moved to their final destinations –the ahu-, those being torn down and erected