"To accompany the transformations I wanted a completely unrealistic sound. First I tried rhythmic beats, like a heartbeat. We tried every sort of drum, but they all sounded like drums. Then I recorded my own heart beating, and it was perfect, marvellous. Then we recorded a gong, took off the actual impact noise, and reversed the reverberations. Finally we painted on the sound track; and I think that was the first time anyone had used synthetic sound like that, working from light to sound."