I found it weird that the first 3 expressions of the opening motif, while each was visually an octave lower on the keyboard, all sounded in exactly the same register. Then after the 3rd motif, as an arpeggio went up the keyboard, the notes that had been the same pitches as the lowest were now one and two octaves higher. But then, the middle register that sounded middle only during the arpeggio, reverted to same-as-lower register when the two were playing together. That's where I stopped watching, so I could ask if anyone else noticed this?