The last of the 'official' 24 Etudes of Chopin is a force of nature. It hardly sounds like a piano at all; it sounds like a full orchestra, consisting as it does of huge waves of sound - so much so that for a long time it was known as the "Ocean Wave" Etude. This is not a name Chopin would ever have given it, but it's not a bad description, Rather than the ocean, however, it is perhaps more like a great cathedral in sound. However, pictorialism is not the goal of music: great music is a window on the soul, one through which we are permitted to perceive archetypal emotions, universal to everyone. Nevertheless, no composer ever made a piano sound like this before and no one ever would again - not even Chopin's exuberant friend Liszt. Once or twice Rachmaninoff achieved this kind of 'wall of sound' effect, but never surpassing Chopin's example. Technically this Etude is quite difficult - not overly difficult, but nevertheless it presents real problems of co-ordination between the hands. However the essence of this Etude is its sheer overwhelming sound - and of course, it's emotional impact.