... THE remarkable musical puzzle on the right is the same tune, note for note, whether you play it upside down or right way up. Left hand becomes right hand, and vice versa. It can only be described as a unique stroke of genius, for it is tuneful, interesting, spontaneous and without a jarring note. A close friend of Mendelssohn, Ignaz Moscheles (1794-1870), leading pianist, was its composer, and ...