and Fugue in D minor. Moór duplex measures makes it easier for the pianist to play difficult passages: - It has a lot of strings and hammers. - The upper, 74 key keyboard connects through a linkage with the key on a lower octave lower on the keyboard. - An optional fouth pair of pedal allows lower to the upper keyboard, thus playing octaves with a single key. - The increased buttons on the tails of the lower keys allow a chromatic glissando. Although it looks similar to a two-harpsichord…

http://www.youtube.com/watch?v=3oAuEN91cpU&hl=en