Sentence:  Nick had heard her play through the very beginning of it a dozen times, until he was screaming at her in his head to go on. Well, now she did, watching her own hands busying up and down the keyboard as if they were astonishing <WSD>automata</WSD> that she had wound up and set in motion, in perfect synchrony, to produce this silvery flow of sound. 
Meaning of the word marked with <WSD> tags:  A machine or robot designed to follow a precise sequence of instructions.