and in other cases, the imitation is aesthetically processed, aestheticised. instance, if you hear a crow and you make a crow sound, that's iconic imitation. but if you hear water, it's hard to make a sound that's exactly like water. and what they do is that they kind of fantasize on the sound of water. and they use this remarkable technique that's become known in the west as throat singing, to imitate the sound of water for instance. and not only to imitate it but to interact with it. traditionally, what singers did was to stand by a stream or sit by a stream and sing to the spirit of the stream. and our work in tuva is an attempt to capture this whole relationship between humankind and the natural world through this kind of music. in throat singing, which the tuvans call khoomei, and it's also called overtone singing in the west, what you're doing is selectively amplifying harmonics which are naturally present in the voice, and thus singing two pitches at the same time-- a fundamental pitch and a harmonic pitch. and i'll try to demonstrate that. [singing sam